Complex machining machine tool

ABSTRACT

A complex machine tool has a single frame having a chip collecting space at a center portion thereof, first and second spindle stocks on the frame, relatively free to move and drive in a Z axis direction and holding the chip collecting space therebetween, workpiece spindles on the spindle stocks free to rotate and drive and facing each other, and tool rests. The tool rests have turrets and can assume various kinds of movement. Complicated and varied types of machining can be performed combining the rotation control of the workpiece spindles and the spindle stocks.

This is a division of Ser. No. 07/337,881, filed on Apr. 14, 1989 whichis a division of Ser. No. 07/182,452, filed Apr. 18, 1988 now U.S. Pat.No. 4,949,444.

BACKGROUND OF THE INVENTION

This invention relates to a complex machine tool having mutually facingworkpiece spindles, provided with respective tool rests corresponding tothe workpiece spindles.

In recent years, the machining operations of machine tools have beencomplicated and varied, and the efficiency demanded for machine tools inthe future is going to be high.

In consideration of the above-described circumstances, the object of thepresent invention is to provide a complex machine tool which can executecomplicated machining operations and machining methods using the machinetool.

SUMMARY OF THE INVENTION

The present invention provides tool rests independently disposed to befree to move and drive and corresponding to respective spindle stocks.Turrets on which one or more tools can be installed are provided on theinside of each tool rest, being free to index, rotate and drive atpredetermined machining positions. The tool installation portion of eachturret is provided to project in the further negative direction on an Xaxis in comparison with a portion of the tool rest positioned in themost negative direction of the X axis when the tool installation portionis indexed to a machining position.

According to the above-described arrangement of the machine tool adistance L between a tool installed in the turret and the workpiecespindle, as for example seen in FIG. 3, can be longer in comparison withwhen the turrets are installed to the outside of the tool rests and thetools are disposed at the outside of the tool rests, since the turretsare positioned to the inside of the tool rests. Furthermore, the minimumlength of a workpiece able to be machined can be longer with the samemachine dimension in the Z axis direction. Therefore, the machinedimension can be smaller if the maximum length of the workpiece is thesame, and the machine can be made more compact.

Since a tool installation surface of the turret is positioned to projectin the further negative direction of the X axis in comparison with thetool rest, the machining is performed on a workpiece by means of thetool by having the tool rotated on the turret and indexed at a machiningposition Xl. Thereafter the tool rest is moved in the negative directionof the X axis. The tool to be used for machining always projects fromthe tool rest toward the workpiece side of the tool rest. Therefore, themachining can be sufficiently performed on the workpiece by theprovision of a guide means of a short length, such as sliding surface.The guide means of the tool rest is disposed at a position which doesnot intercept the Z axis, in comparison with the tool rest, in which thetools are installed like the teeth of a comb. Accordingly, the problemof chips interfering with the guide means can be eliminated. Also, thechip collecting function can be smoothly performed, since a chipcollecting spaced is not interrupted by the guide means.

The spindle stocks can also be provided to be free to move and drive inthe Z axis direction, enabling the spindle stocks to be synchronouslyand asynchronously moved with respect to each other. Therefore variedmachining operations can be performed, such as machining a long sizedworkpiece held between both of the spindle stocks.

A first workpiece handling means may be provided corresponding to thefirst spindle stock, and a second workpiece handling means may beprovided corresponding to the second spindle stock. A first workpieceholding portion of the first workpiece handling means is movable onlybetween a first waiting position and a first workpiece delivery positionfacing the first workpiece spindle. A second workpiece holding portionof the second workpiece handling means is moveable only between a secondwaiting position and a second workpiece delivery position facing thesecond workpiece spindle. A workpiece can be attached to the firstspindle stock by having the workpiece held by the first workpieceholding portion of the first workpiece handling means. The firstworkpiece holding portion is then moved from the first waiting positionto position the workpiece at a first workpiece delivery position X2. Thefirst spindle stock is then moved to the workpiece in the Z axisdirection to complete delivery of the workpiece to the first spindlestock. The workpiece can be detached from the second spindle stock byhaving the second workpiece holding portion of the second workpiecehandling means positioned at the second workpiece delivery position.Thereafter the second spindle stock is moved together with the workpieceto the second workpiece holding portion positioned at the secondworkpiece delivery position in the Z axis direction to complete deliveryof the workpiece to the second workpiece holding portion.

The workpiece can be fed from one spindle stock to the other spindlestock without the use of a handling robot or the like by having bothspindle stocks approach each other by relative movement in the Z axisdirection, and the workpiece held by one workpiece spindle is thendelivered to the other workpiece spindle.

When machining a long sized workpiece the workpiece is held by eachworkpiece holding portion of both the first and the second workpiecehandling means. The workpiece holding portions are then synchronouslymoved to position the workpiece between the spindle stocks. Furthermore,both spindle stocks are moved in the Z axis direction to approach theworkpiece. In this way the workpiece can be held by both workpiecespindles.

When cutting-off machining of the workpieces being held by both theworkpiece spindles is to be performed, the workpiece holding portions ofthe first and the second workpiece handling means are positioned at afirst workpiece delivery position X2 and a second workpiece deliveryposition X4, respectively. The workpieces are rotatably held by therespective workpiece holding portions, and the workpieces can be cutoff.

As a result, various movements, such as the attachment and detachment ofvarious workpieces of the two spindle stocks, the holding of workpiecesduring cutting-off machining, and the like, can be performed by thefirst and/or the second workpiece handling means, which have no functionof moving in the Z axis direction. Furthermore, since the workpiece canbe directly delivered between the spindle stocks, it is not necessaryfor the workpiece handling means to have the function of moving in the Zaxis direction. Therefore the control procedures and the arrangements ofthe handling means can be simplified.

Machining can be continued by having the workpiece delivered between thespindle stocks by means of a barfeeder, the machined workpiece beingtaken out only by the second handling means. As a result, a complexmachine tool by which various workpiece machining operations can beperformed can be provided. Furthermore, the handling means can easilyhold the workpiece. The movement quantity of the spindle stocks in the Zaxis direction is controlled by means of a machining program if thelength of the workpiece to be machined varies. As a result, the movementof the workpiece handling means can be kept to a minimum, and thecontrol of the workpiece handling means can be simplified in comparisonwith the earlier discussed workpiece handling means. Moreover, since thehandling means do not move in the Z axis direction, an operator will notcollide the handling means with other components and can machine theworkpiece safely.

A workpiece supporting means, by which a workpiece may be rotatablysupported, can be disposed on the tool rest. The workpiece can then besupported by the workpiece supporting means when the tool rest is movedand driven. Accordingly, it is not necessary to provide a separatecenter rest apparatus, or a sliding surface and a driving source formoving the center rest apparatus. When the workpiece supporting means isdriven by means of a tool rotating drive mechanism of the tool rest, itis not necessary to provide independent drive sources for the workpiecesupporting means. Therefore the center rest can be smaller and itsstructure can be simplified.

Furthermore, if the workpiece spindles are synchronously rotated, aworkpiece can be delivered between the workpiece spindles withoutstopping the workpiece spindles, and the machining of along sizedworkpiece can be performed while supporting the workpiece between theworkpiece spindles.

That is, a first routine of machining is performed with the workpieceheld by the first workpiece spindle, and a second routine of machiningis performed by having the machined workpiece, after the first routine,delivered to the second workpiece spindle, a synchronous rotatingcontrol means for the workpiece spindles being provided. When themachined workpiece, after the first routine, is delivered to the secondworkpiece spindle from the first workpiece spindle, the first workpiecespindle and the second workpiece spindle are rotated at the samerotation number by means of the synchronous rotating control means. Thenthe first and second workpiece spindles approach each other. Theworkpiece is then held by the second workpiece spindle. The holdingrelation between the workpiece and the first workpiece spindle is thenreleased. With the above-described method, the second routine ofmachining can be immediately performed, the first and the secondworkpiece spindles being synchronously rotated without stopping theirrotation, and the machined workpiece, after the first routine, beingdelivered to the second workpiece spindle from the first workpiecespindle in a rotating state. The machining time of the workpiece canthus be shortened.

Moreover, a spindle driving motor control means, by which the rotationof the spindle driving motors are controlled, is connected with thespindle driving motors of the first and the second workpiece spindles.When machining a long sized workpiece supported between the first andthe second workpiece spindles, the spindle driving motor control meansis driven, and one spindle driving motor of the spindle driving motorsis rotated at a predetermined torque. At the same time, the otherspindle driving motor is rotated and driven at a smaller torque than thepredetermined torque. In this state a predetermined machining isperformed on the workpiece. With the above-described arrangement, therotation angular velocity quantity of the workpiece spindles iscontrolled by the spindle driving motor rotating and driving at thepredetermined torque. The workpiece spindles are synchronously rotatedat the rotation angular velocity quantity of the one spindle connectedwith the driving motor if the characteristics of the workpiece spindles(inertia, the characteristics of adjustable speed and the like) do notcorrespond with each other. As a result, harmful torsional torque iseffectively prevented from acting on the workpiece being held betweenworkpiece spindles, and the workpiece can be machined in this state.

The spindle driving motor control means, by which the rotation of thespindle driving motors is controlled, is connected with the spindledriving motors of the first and the second workpiece spindles. Whenmachining, a workpiece is held between the workpiece spindles.Thereafter, when the spindle driving motors are energized in this state,the spindle driving motor control means is driven. One spindle drivingmotor holds itself and the other spindle driving motor is rotated at thepredetermined torque. The self-holding of the one spindle driving motoris released, and the spindle driving motor is rotated at thepredetermined torque. With the above-described method, since theworkpiece spindles are driven by their respective spindle drivingmotors, the inertia of the spindle connected with the other spindledriving motor does not act on the workpiece. Therefore, excessivetorsional torque can be effectively prevented from acting on theworkpiece at the time of energizing.

Moreover, the first tool rest may be provided in a first movement areamovable in the Z axis direction, and the second tool rest may bedrivably provided in a second movement area, having a common movementarea overlapping with the first movement area. With the above-describedarrangement, the portion to be machined of a long sized workpiece ispositioned at a position corresponding to the common movement area. Theworkpiece can then be machined by only the tool installed in the firstor the second tool rest. At the same time, the machining of the longsized workpiece can be easily performed by having the portion to bemachined moved in the common movement area. The portion of the workpiecepositioned in the common movement area can be machined by means of thefirst or the second tool rest. Accordingly, it is not necessary toinstall the same tool in both the first and the second tool rests, andthe tools can be more effectively installed in the tool rests. Since thecontrol of machining is then also performed for only one tool rest, themachining program is more easily planned and executed.

A workpiece may be held by the first workpiece spindle. In this state,machining is performed on the workpiece. After the machining, the firstand the second workpiece spindles are moved in a rotation angularcontrol direction, such as a C-axis direction, and are positioned atpredetermined delivery positions. At the same time, the first and thesecond workpiece spindles approach each other to hold the workpiece.Thereafter, the holding relation between the workpiece and the firstworkpiece spindle is released, the first and the second workpiecespindles are then separated from each other whereby the workpiece isheld by the second workpiece spindle side of the machine. Apredetermined machining is then performed on the workpiece. With theabove-described method, the first and the second workpiece spindles arepositioned at the delivery positions. In this state, the workpiece,being held at the first workpiece spindle side, can be directlydelivered to the second workpiece spindle side with movement on therotation angular control axis being restricted. As a result, theworkpiece can be delivered to the second workpiece side from the firstworkpiece spindle side without generating a phase shift from a rotationangular control origin, such as a C-axis origin, and a milling machiningoperation and the like, accompanied by the rotation angular control,such as the C-axis control, can be accurately performed on the deliveredworkpiece.

Furthermore, a workpiece center rest means is installed on at least oneof the first and the second tool rests. When machining a long sizedworkpiece, one end portion of the workpiece is held by the first or thesecond spindle stock with the workpiece spindle. At the same time, theworkpiece is supported by the workpiece center rest means installed onthe first or the second tool rest. If the other end portion of theworkpiece is to be machined by means of a tool installed on the othertool rest, different from the tool rest supporting the above-describedworkpiece, the end portion of the workpiece is machined with the endportion of the long sized workpiece supported by the workpiece centerrest means installed on the first or the second tool rest. As a result,it is not necessary to provide a workpiece center rest apparatus on thecomplex machine tool which would extend through the sliding surface orthe like, and the machine tool does not become overly large andcomplicated. After one end portion of the long sized workpiece held bythe first spindle stock is machined, the end portion of the workpiece ispulled out of the workpiece spindle, and can be machined by having thefirst and the second spindle stocks approach each other and theworkpiece delivered to the second spindle stock side. As a result, bothend portions of the long sized workpiece can be machined withoutinverting the workpiece, the efficiency of the operation can be improvedand the amount of labor required reduced.

In addition, a workpiece can be held by the first spindle stock, and afirst routine of machining performed thereon.

After the first routine, a first step is executed. That is, the secondspindle stock is moved a predetermined distance toward the first spindlestock, and the workpiece is held by the first and the second spindlestocks.

In this state, a second step is then executed. That is, the workpiece iscur off while synchronously rotating the first and the second spindlestocks. The part cut off from the workpiece is held by the secondspindle stock.

Furthermore, a third step is executed. That is, the second spindle stockis moved together with the part the predetermined distance to theoriginal position separated from the first spindle stock.

In this state, a fourth step is executed. That is, the first routine ofmachining is performed on the workpiece being held by the first spindlestock. At the same time a fifth step is executed. That is, a secondroutine of machining is performed on the part being held by the secondspindle stock.

Furthermore, the workpiece is fed a predetermined length from the firstspindle stock during the first step through the fourth step. In the caseof the above-described method, after the first routine, the partincluding the portion to which the first routine is finished is cut offfrom the other raw portion of the workpiece while being held by thesecond spindle stock. As a result, the first and the second routines ofmachining can be performed and parts of a predetermined shape can besuccessively made without requiring the intervention of an operator.

Moreover, a workpiece can be held by the first spindle stock, and afirst routine of machining can be performed thereon. After the firstroutine, the second spindle stock is moved a predetermined distancetoward the first spindle stock to hold the workpiece by the first andthe second spindle stocks. In this state the holding relation betweenthe first spindle stock and the workpiece is released. The secondspindle stock is then moved a position distant the predetermineddistance from the first spindle stock. The workpiece is then pulled outa length equal to the predetermined distance from the first spindlestock, and the workpiece is held by both the first and the secondspindle stocks. Thereafter, the workpiece is cut off while the first andthe second spindle stocks are synchronously rotated. The part cut offfrom the workpiece is held by the second stock. Furthermore, the secondspindle stock is moved together with the part to a position separatedthe predetermined distance from the first spindle stock. The firstroutine of machining is then performed on the workpiece being held bythe first spindle stock. At the same time, a second routine of machiningis performed on the part being held by the second spindle stock. In theabove-described method, in addition to the above-described effects, theworkpiece can be cut off by having the predetermined length of theworkpiece pulled out from the first spindle stock by the second spindlestock without using the barfeeder apparatus.

In the method comprising a first, a second, and a third step asdescribed below, the first through the third steps are executed one timeor more than one time. That is, the first step is as follows: after apredetermined machining is performed with a workpiece held by the firstand the second spindle stocks, the holding relation between the secondspindle stock and the workpiece is released. In this state the secondspindle stock is moved toward the first spindle stock and the workpieceis again held by the first and the second spindle stocks. The secondstep is as follows: when the workpiece is held by the first and thesecond spindle stocks, the holding relation between the first spindlestock and the workpiece is released. The second spindle stock is thenmoved together with the workpiece to a position distant a predetermineddistance from the first spindle stock. The raw portion of the workpieceis thus pulled out a length equal to the predetermined distance from thefirst spindle stock. The third step is as follows: when the raw portionof the workpiece is pulled out the predetermined length from the firstspindle stock, the pulled out raw portion of the workpiece is heldbetween the first and the second spindle stocks. Then the machining isperformed toward the raw portion. With the above-described method, theworkpiece can be intermittently pulled out the predetermined length fromthe first spindle stock by means of the second spindle stock. As aresult, the workpiece can be intermittently pulled out the predeterminedlength from the first spindle stock without using a specific apparatus,such as a barfeeder apparatus, and the raw portion of the workpiecewhich is pulled out can be machined by holding it between the first andthe second spindle stocks.

In the machining of the third step, the portion to be machined ispositioned near the first or the second workpiece spindle and in thisstate the machining is performed. With the above-described method, sincethe workpiece is always machined at a position adjacent to a workpiecespindle, the workpiece spindle holding the workpiece fills the role of acenter rest. Therefore chattering or the like can be effectivelyprevented from being generated on the workpiece during the machining,and the machining accuracy can be improved.

A workpiece is held by a chuck installed on the first spindle stock soas not to rotate on the chuck and so as to be moveable in the Z axisdirection. Furthermore, the second spindle stock is moved apredetermined distance toward the first spindle stock to hold the endportion of the workpiece. In this state the raw portion of the workpieceis pulled out from the first spindle stock with the second spindlestock, the second spindle stock moving together with the workpiece inthe direction going away from the first spindle stock. The pulled outraw portion is then machined by means of the tool rest positioned at aposition adjacent to the first spindle stock. With the above-describedmethod, the raw portion can be machined at a position adjacent the firstspindle stock by means of the tool rest, the raw portion of theworkpiece being pulled out from the first spindle stock by means of thesecond spindle stock. Therefore the workpiece can be machined withoutusing the barfeeder apparatus. Since the machining is performed at aposition adjacent to the spindle stock, the chuck installed on the firstspindle stock can fill the role of the center rest during the machiningof the workpiece, and the machining can be performed with high accuracywithout the center rest.

Different kinds of workpieces can be held by the workpiece spindlesusing the workpiece holding means. Predetermined machinings areperformed on the workpieces to form connecting portions on therespective workpieces. After the machining, the first and the secondspindle stocks are relatively moved together with the workpieces toapproach each other. The workpieces are then assembled through theconnecting portions. With the above-described method, connecting partscan be made such that workpieces are connected through connectingportions. As a result, the machining and assembly of certain kinds ofworkpieces can be automatically performed by one complex machine toolwithout requiring the assistance of an operator and without providing anassembly line for assembling the workpieces.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a first embodiment of a complexmachine tool according to the present invention;

FIG. 2 is a front elevation of the complex machining machine tool ofFIG. 1;

FIG. 3 is a top view of FIG. 2;

FIG. 4 is a sectional view along the line IV--IV of FIG. 2;

FIG. 5 is a front elevational view showing a second embodiment of acomplex machine tool according to the present invention;

FIG. 6 is a left side elevation of FIG. 1;

FIG. 7 is a front elevation showing a loading apparatus installed in thecomplex machine tool as shown in FIG. 5;

FIG. 8 is a partly sectional view showing an important feature of theloading apparatus of FIG. 7;

FIGS. 9 through 17 are flow charts illustrating the machining of aworkpiece by means of the complex machine tool as shown in FIG. 5;

FIGS. 18 through 23 are flow charts illustrating the machining of a longsized workpiece by means of the complex machine tool as shown in FIG. 5;

FIG. 24 shows another example of a hand of loading apparatus;

FIG. 25 is a front elevation showing a third embodiment of a complexmachine tool according to the present invention;

FIG. 26 is a sectional view along line II--II of FIG. 25;

FIG. 27 is a view seen by the arrow YIII of FIG. 25;

FIG. 28 shows the relation of the positions between two tool rests ofthe complex machine tool as shown in FIG. 25;

FIG. 29 is a front elevation showing a tool rest of the complex machinetool as shown in FIG. 25;

FIG. 30 shows an example of a workpiece center rest apparatus installedin a tool rest;

FIG. 31 shows an engagement condition between a workpiece center restapparatus and a workpiece;

FIGS. 32 through 39 illustrate a process by which a machining isperformed on a shaft shaped workpiece by means of the complex machinetool as shown in FIG. 25;

FIG. 40 illustrates a method of machining a shaft shaped workpiece afterthe workpiece is supported by a face driver;

FIGS. 41 through 44 illustrate a process by which a bar shaped workpiecemachining is performed with the complex machine tool as shown in FIG.25;

FIGS. 45 through 51 illustrate an example of a process by whichconnecting parts are successively made the complex machine tool as shownin FIG. 25;

FIGS. 52 through 58 illustrate another example of a process by whichconnecting parts are successively made by the complex machine tool asshown in FIG. 25;

FIGS. 59 through 63 illustrate an example of a process by which chuckedworkpiece machining is successively performed on one type of a workpieceby the complex machine tool as shown in FIG. 25;

FIGS. 64 through 66 illustrate an example of a process by which chuckedworkpiece machining is successively performed on two types of workpiecesby the complex machine tool as shown in FIG. 25;

FIGS. 67 and 68 illustrate another example of a process by which chuckedworkpiece machining is successively performed on two types of workpiecesby the complex machine tool as shown in FIG. 25;

FIGS. 69 and 70 illustrate yet another example of a process by whichchucked workpiece machining is successively performed on two types ofworkpieces by the complex machine tool as shown in FIG. 25;

FIG. 71 is an elevated view showing an example of the driving structureof a spindle stock in a complex machine tool;

FIG. 72 is a top view of a complex machine tool;

FIG. 73 is a top view showing another example of the driving structureof a spindle stock in a complex machine tool;

FIGS. 74 through 81 illustrate a method of bar shaped workpiecemachining with the complex machine tool as shown in FIG. 71;

FIGS. 82 through 88 illustrate a method which a long and slender sizedshaft workpiece is machined by the complex machine tool as shown in FIG.71;

FIGS. 89 90,A and 90,B illustrate a method of barfeeder machining by thecomplex machine tool as shown in FIG. 71;

FIG. 91 is a schematic view showing an embodiment of a method of drivingthe spindle stocks in a complex machine tool;

FIGS. 92 through 99 illustrate a method of machining a long and slendershaft workpiece;

FIG. 100 is a control block diagram showing an example if a complexmachine tool;

FIG. 101 is a top view of the complex machine tool as shown in FIG. 100;

FIGS. 102 through 109 illustrate way of a machining of a workpiecemaking use of a embodiment of a machining control method in a complexmachine tool;

FIG. 110 is a view seen by the arrow WQ toward a workpiece in FIG. 104;

FIG. 111 is a view seen by the arrow WR toward a workpiece in FIG. 109;

FIG. 112 is a control block diagram showing an example of a complexmachine tool;

FIG. 113 is a control block diagram showing an example of a controlcircuit of a spindle driving motor;

FIG. 114 is a schematic view of a part of a spindle stock;

FIG. 115 is a control block diagram showing an example of a machine toolfor which a coordinate system control method is applied;

FIG. 116 illustrates the relationship of each of the coordinate system.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The preferred embodiment of the present invention will now be describedhereinafter with reference to the accompanying drawings.

FIG. 1 through FIG. 4 indicate a first embodiment of a complex machiningmachine tool.

A complex machining machine tool 1 has a single frame 2 as shown in FIG.1 through FIG. 3. At the center portion of a frame 2, a chip collectingspace 4, having a width of W1, is formed in the direction of arrows Cand D, shaped so as to nearly part the frame 2 in the right and leftdirections of FIG. 1. On both sides holding the chip collecting space 4of the frame 2, guide rails 2a and 2b are separately formed in thedirection of arrows A and B, that is, in a Z axis direction,respectively. On each of guide rails 2a and 2b is movably provided arespective spindle stock 5 or 6, movable in the direction of the arrowsA and B along the guide rails 2a and 2b. At each of the spindle stocks 5and 6, a workpiece spindle 5b or 6b, comprising a workpiece holdingmeans, such as a chuck 5a, 6a or the like, is rotatably supported by arespective drive motor mounted in each of the spindle stocks 5 and 6.The workpiece spindles 5b and 6b are provided so as to face each otheron the Z axis, and in such a manner that the centers of rotationcorrespond to each other, as shown in FIG. 3. More specifically, on theframe 2, guide rails 2c and 2d are formed so as to frame the chipcollecting space 4 and face together in the X axis direction,perpendicular to the Z axis direction, that is, in the direction of thearrows C and D.

On each of the guide rails 2c and 2d is a respective tool rest 7 or 9,movably and drivably provided along the guide rails 2c and 2d only inthe directions of arrows C and D. At each of tool rest 7 and 9 isprovided a respective turret 7a or 9a, each turret being free to indexand rotate on a rotation axis RA, so as to face in the same directionparallel with the Z axis as its center, in the directions of arrows Eand F, as shown in FIG. 3. Each of turrets 7a and 9a is provided so asto project inside of the tool rests 7 and 9 in FIG. 3, that is, abovethe chip collecting space 4. More specifically, a tool installationsurface 7b or 9b of the turrets 7a and 9a is provided so as to projectin the negative direction on the X axis, that is, in the D direction,toward the front face of the tool rest 7c and 9 c. The tool installationsurfaces project in the negative direction on the X axis of the toolrests 7 and 9 the most when each tool installation surface 7b and 9b ispositioned at a machining position X1, as shown in FIG. 1 and FIG. 4.With each tool installation surface 7b and 9b, a plurality of tools 10,such as a rotation tool and a turning tool and the like, are attached.

In the chip collecting space 4, a chip collecting bucket 11, as shown inFIG. 1, is provided so as to be capable of being inserted and pulled outin the direction of the arrows C and D of FIG. 3.

With the above-described constitution of the complex machining machinetool 1, when workpiece is machined using the complex machining machinetool 1, the workpiece to be machined is held by one of chucks 5a and 6aof the respective spindle stocks 5 and 6 or is held between the chucks5a and 6a of the spindle stocks 5 and 6, as shown in FIG. 1 through FIG.4. Thereafter, the workpicce spindle 5b or 6b is rotated with the X axisas its center. In the foregoing state, the spindle stock 5 or 6 is movedin the directions of arrows A and B along the guide rail 2a or 2b. Therespective turret 7a or 9a of the tool rest 7 or 9 is rotated. Next, thetool installation surface 7b or 9b, on which is installed the tool 10used for machining, is indexed and positioned at the predeterminedmachining position Xl. At the time the tool 10 is indexed, the tool rest7 or 9 is moved along the guide rail 2c or 2d in the direction of thearrows C and D, that is, in the X axis direction, to perform thepredetermined machining on the workpiece which is installed on theworkpiece spindle 5b or 6 b.

When a workpiece is installed on each of the workpiece spindles 5b and6b, each of the workpiece spindles 5b and 6b is driven and controlledindependently. The rotating speed, feed rate and feed direction in the Zaxis direction and the like are also driven and controlled such thateach spindle stock 5 and 6 is independent. It is natural that the toolrest 7 or 9 on which is installed the tool 10 for machining of theworkpiece is driven and controlled so as to be independent in the X axisdirection. But it is obvious that the turret 7a or 9a projects its toolinstallation surface 7b or 9b above the chip collecting space 4 and thatthe turret 7a or 9a moves together with the tool rest 7 or 9 only in theX axis direction, as shown in FIG. 3. Therefore, the area that the tipcf the tool 10, which is installed on the turret 7a or 9a, movestogether with the movement of the upper space of the chip collectingspace 4. Thus, the tool 10 naturally contacts a workpiece at a positionprojecting over the chip collecting space 4 to perform the machining.The chips produced immediately fall and are collected in the chipcollecting space 4. The machining area MA in which the tool 10 contactsa workpiece to perform the machining is almost located on the chipcollecting space 4 with respect to grade level, as shown in the hatchedpart of FIG. 3. Since the tool installation surface 7b or 9b projectsfrom the front face 7c or 9c of the tool rest 7 or 9 in the negativedirection on the X axis, that is, the arrow D direction, the machiningmovements are performed smoothly without interference of the workpieceby the tool rest 7 or 9 at the time of machining.

On the other hand, when the machining is performed such that a workpieceis held between both workpiece spindles 5b and 6b, the workpiecespindles 5b and 6b are synchronously rotated and driven. At the sametime, the work piece spindles 5b and 6b are also synchronously moved inthe direction of arrows A and B. In the foregoing state, the tool rests7 and 9 are moved and controlled so as to be independent of each otherin the directions of the arrows C and D to perform the machining to theworkpiece by means of the turrets 7a and 9a.

Another embodiment of a complex machining machine tool will be describedin FIG. 5 through FIG. 24.

A complex machining machine tool 100 has a machine body 102, as shown inFIG. 5. On the machine body 102, spindle stocks 103 and 105 face eachother so that shaft centers XCT1 and XCT2 of the spindles 103a and 105acorrespond, as will be described later, and are movably and drivablydisposed in the direction of arrows XA and XB (that is, in the Z axisdirection). In the spindle stocks 103 and 105, each spindle 103a and 105is rotatably and drivably mounted, with shaft centers XCT1 and XCT2 astheir center, in the directions of arrows XC and XD, respectively. Inthe spindles 103a and 105a are installed chucks 103b and 105b,respectively.

On the machine body 102, two carriages (only one carriage is shown inFIG. 6), which constitute the tool rests 106, are provided so as tocorrespond with the spindles 103a and 105a and are movable and drivablethrough respective guide members 102b in the horizontal direction towardthe sheet of the figure (that is, in the direction of arrows XA and XBof FIG. 5), as shown in FIG. 6, respectively. A carriage 106a, as shownin FIG. 6, has a main body of a tool rest 106b provided movably anddrivably thereon in the direction of XE and XF, respectively. Thisdirection is the vertical direction of arrows XA and XB, that is, the Zaxis direction. With the body of the tool rest 106b is rotatably anddrivably provided a tool installation portion 106c, a type of turret,enabling the installation of a plurality of tools.

By the way, at the front surface 102c of the machine body 102 in FIG. 5are installed two loading apparatus 109A and 109B adjacent the spindlestocks 103 and 105, respectively. The loading apparatus 109A and 109Bhave a body 110, an arm 117 and a hand 109. That is, on the frontsurface 102c of the machine body 102 as shown in FIG. 7, the body 110 isinstalled. The body 110 has a box-like casing 111. In the casing 111, anarm turning cylinder 112 is installed through a pin 112c. With the armturning cylinder 112 is supported a rod 112a, which is free to projectand to recede in the directions of arrows XG and XH. At the edge portionof the rod 112a in the figure, a connecting member 112b is installed. Atthe upper left hand portion of the arm turning cylinder in FIG. 7, alever support portion 111a of the casing 111 is provided. With the leversupport portion of 111a, a lever 113 is supported so as to be free toturn, through a pin 113b, in the directions of arrows X1 and XJ. In thecenter portion of the lever 113 in FIG. 7, the connecting member 112b,which is installed in the rod 112a of the arm turning cylinder 112, isinstalled through the pin 113a. Furthermore, at the right edge portionof the lever 113 in the figure, a roller 113c is rotatably provided.

At the oblique portion to the right above the arm turning cylinder 112in FIG. 7 is disposed a bearing portion 111b of the casing 111. Anengaging shaft 115 in the bearing portion 111b, projects a right endportion 115b to the outside of the casing 111, as shown in FIG. 8, andis rotatably supported with the shaft center XCT3 of the shaft 115 asits center in the directions of arrows XK and XL. An engaging member 116is installed through a boss portion 116a of the engaging member 116 withthe left end portion 115a of the engaging shaft 115. A plate 116b of theengaging member 116 is provided so as to jut out in a right-angledirection toward the shaft center XCT3 of the engaging shaft 115. On theplate 116b is formed an engaging slot 116c. A roller 113c of the lever113 is fitted in and engaged with the slot 116c so as to be free toturn.

At the right end portion 115b of the engaging shaft 115 in FIG. 8, thearm 117 is connected so as to be able to oscillate together with theengaging shaft 115 in the direction of arrows XK and XL. At the end ofthe arm 117 in FIG. 7 is provided the hand 119. The hand 119 has abox-like main frame 120. Clamp portions 121a and 121b for holding theworkpiece are provided with the main frame 120. The clamp portions 121aand 121b have driving cylinders 122A and 122B and clamps 125a and 125b,respectively. The driving cylinders 122A and 122B are provided in themain frame 120. The driving cylinders 122A and 122B each have a supportrod 122a, a piston 122b and a cylinder 122c. The support rods 122a ofthe driving cylinders 122A and 122B are provided in such a manner thatthe upper and lower portions of the support rod 122a in FIG. 7 areconnected with an upper plate 120a and a lower plate 120 b of the mainframe 120, respectively. At the center portion of each support rod 122ais stationarily disposed the respective piston 122b. Furthermore, acylinder 122c is slidably engaged with the support rod 122a and with thepiston 122b on its surrounding inside surface, and is mounted so as tobe free to move in the up and down directions in FIG. 7 along thesupport rod 122a. In the cylinders 122c is formed an oil chamber 122d insuch a manner that the support rod 122a is covered. At a head portion122e and a bottom portion 122f of each cylinder 122c, the pipes whichare connected with the hydraulic apparatus (not shown) are connected insuch a manner that pressurized oil is able to supply the oil chamber122d. At the lower side surface of the cylinder 122c of the drivingcylinder 122A in FIG. 7 are formed plurality of cogs 122g atpredetermined intervals in the directions of arrows XM and XN. Arotatably mounted cog wheel 127 is meshed with these cogs 122g.

Furthermore, at the upper side surface cf the cylinder 122c of thedriving cylinder 122A in FIG. 7, a reverse J-form support bar 123 ismovably mounted together with the cylinder 122c in the directions ofarrows XM and XN. A bending portion 123a is formed on the support bar123 so as to project from the main body 120 in the arrow XN direction.At the top portion of the bending portion 123a in the figure is provideda clamp 125a. At the clamp 125a a workpiece holding portion 125c isformed in a V-form shape perpendicular to the paper surface in FIG. 7.

At the upper side surface of the cylinder 122c of the driving cylinder122B in FIG. 7, a support bar 126 is movably provided together with thecylinder 122c in the directions of arrows XM and XN. With the supportbar 126, a clamp 125b projects from the main body 120 in the directionas shown by arrow XN, and is disposed so as to face the clamp 125a. Aworkpiece holding portion 125c on the clamp 125b is formed in a V-formshape perpendicular to the paper surface in FIG. 7. At the right endportion of the support bar 126, which is inserted in the main body 120in the figure, a stepped portion 126a is disposed facing the cog wheel127. Plural cogs 126b are formed on the stepped portion 126a atpredetermined intervals in the directions of arrows XM and XN. The cogs126b are engaged with the cog wheel 127.

Furthermore, a cover 135 is provided to cover the main body 102 of thecomplex machining machine tool 100, as shown in FIG. 6. And, at both theright side and the left side of the complex machining machine tool 100in FIG. 5, a bar feeder 143 is provided such that a bar shaped workpiececan be supplied to the chucks 103b and 105b through the spindles 103aand 105a, respectively.

With the above-described constitution of the complex machining machinetool 100, when a workpiece 131 is required to be machined, at first theworkpiece 131 to be machined is installed in the chuck 103b by using theloading apparatus 109A of left hand in FIG. 5. To do this, the operatorinserts the workpiece 131 between the clamps 125a and 125b of the hand119, which is positioned at a waiting position XX1 as shown by full lineFIG. 6. In the foregoing state, the hydraulic apparatus (not shown) isdriven to supply the inside of the cylinder 122c with the pressurizedoil from the side of the bottom portion 122f of the driving cylinder122A, as shown in FIG. 7, and to drain the pressure oil in the oilchamber 122d from the side of the head portion 122e. At the same time,the pressure oil is supplied from the side of the head portion 122e ofthe driving cylinder 122B to the inside of the cylinder 122c, and thepressure oil in the oil chamber 122d is drained from the side of thebottom portion 122f. Then the cylinder 122c of the driving cylinder 122Amoves along the support rod 122a together with the support bar 123 inthe direction as shown by the arrow XM. It is pushed down by thesupplied pressurized oil and meshes with the cog wheel 127, and itsinside surface in FIG. 7 is slidably contacted with the piston 122b. Atthe same time, the cylinder 122c of the driving cylinder 122B movesalong the support rod 122a together with the support bar 126 in thedirection as shown by the arrow XN in such a manner that it is pushed upby the supplied pressurized oil. The support bar 125 cog wheel 127 andits inside surface in FIG. 7 is slidably contacted with the piston 122b.Then the clamp 125a, which is installed on the support bar 122, moves inthe direction as shown by the arrow XM in FIG. 7, and the clamp 125b,which is installed in the support bar 126, moves in the direction asshown by the arrow XN. Accordingly, the workpiece 131 is gripped andheld by the clamps 125a and 125b. Each clamp 125a and 125b issynchronously moved in the directions of arrows XM and XN at equal speedbecause of the action of the cog wheel 127, the cogs 122g, and the cogs126b. As a result, the workpiece 131 is accurately held at anintermediate position in the directions of arrows XM and XN of theclamps 125a and 125b.

When the workpiece 131 is held by the loading apparatus 109A as shown inFIG. 9, the arm turning cylinder 112 of the loading apparatus 109A asshown in FIG. 7 is driven to retract the rod 112a together with theconnecting member 112b in the direction as shown by the arrow XH, and toposition the rod 112a at the position which is indicated by full linesin the figure. Then the lever 113 rotates and is pulled down by theconnecting member 112b, with the pin 113b acting as its center in thedirection as shown by the arrow XJ. When the lever 113 rotates in thedirection as shown by the arrow XJ, the roller 113c, which is providedon the right end portion of the lever 113 in the figure, also rotates inthe direction as shown by arrow XJ and moves to rotate in the engagingslot 116c in the engaging member 116. The engaging member 116 thusrotates, by being pushed and pressed downward by the roller 113c,together with the engaging shaft 115, with the shaft center CT3 of theshaft 115 as its center, in the direction as shown by the arrow XK. As aresult, the hand 119 moves, because of the arm 117, in the direction asshown by the arrow XK, the workpiece 131 being held by the hand 119 andpositioned at a workpiece delivery position XX2 facing the chuck 103b asshown in FIG. 10.

Next, when the chuck 103b is opened, the driving motor (not shown) fordriving the spindle stock 103 in the Z axis direction (in the directionsof arrows XA and XB) is driven at a lower torque to move the spindlestock 103 together with the chuck 103b toward the hand 119 in thedirection as shown by arrow XB. Then the chuck 103b abuts against theleft edge portion of the workpiece 131 held by the hand 119 in FIG. 10.Furthermore, the chuck 103b pushes the workpiece 131 in the direction asshown by the arrow XB. At this time, since the driving motor moving thespindle stock 103 in the direction as shown by the arrow XB is driven ata low torque, the force at which the spindle stock 103 pushes againstthe workpiece 131 via the chuck 103b in the direction as shown by thearrow XB is weak, so that the hand 119 and the like is not deformed bythe pushing force.

In this way, when the workpiece 131 is pushed against the chuck 103b,the chuck 103b is closed, and the workpiece 131 is held by means of thechuck 103b. Thereafter, in this state, the pressurized oil is suppliedto the inside of each cylinder 122c from the head portion 122e of thedriving cylinder 122A, and the bottom portion 122f of the drivingcylinder 122B, as shown in FIG. 7. At the same time, the pressurized oilwhich had been heretofore supplied to the inside of the cylinder 122c isdrained through the bottom portion 122f of the driving cylinder 122B.Then the cylinder 122c of the driving cylinder 122A moves along thesupport rod 122a in the direction as shown by the arrow XN together withthe support bar 123. The cylinder is pushed up by the pressurized oilwhich is supplied to the inside of the cylinder 122c, meshes with thecog wheel 127, and its inside surface is slidably contacted with thepiston 122b. At the same time, the cylinder 122c of the driving cylinder122B moves along the support rod 122a in the direction as shown by thearrow XM together with the support bar 126. The cylinder is pushed downby the supplied pressurized oil, meshes with the cog wheel 127, and itsinside surface is slidably contacted with the piston 122b. The clamps125a and 125b are thus synchronously opened and moved in the directionsof arrows XN and XM so that the holding relation between the workpiece131 and the clamps 125a and 125b is released.

In this way, when the workpiece 131 is held with the chuck 103b as shownin FIG. 10, and the holding relation between the workpiece 131 and thehand 119 of the loading apparatus 109A is released, the driving motorfor driving the spindle stock 103 in the Z axis direction is driven tomove the spindle stock 103 a predetermined distance together with thechuck 103b in the direction going away from the hand 119, that is, inthe direction as shown by the arrow XA. Furthermore, in this state thearm turning cylinder 112 as shown in FIG. 7 is driven, and the rod 112ais projected together with the connecting member 112b in the directionas shown by the arrow XG. Then the lever 113 turns with the pin 113b asits center, in the direction as shown by the arrow XI, due to beingpushed by the connecting member 112b. When the lever 113 turns in thedirection as shown by the arrow XI, the roller 113c of the lever 113also turns in the direction as shown by the arrow XI while rotating inthe engaging slot 116c of the engaging member 116. The engaging member116 then rotates together with the engaging shaft 115, with the shaftcenter XCT3 of the shaft 115 as its center, in the direction as shown bythe arrow XL, being pushed toward the upper portion of the figure by theroller 113c. As a result, the hand 119 is moved by the arm 117 in thedirection as shown by the arrow XL, and is positioned at the waitingposition XX1 as shown in full lines in FIG. 11.

Next, the chuck 103b, as shown in FIG. 12, is rotated together with theworkpiece 131. In this state, the machining of a first routine isperformed on the workpiece 131 by means of a tool 133 in such a mannerthat the tool rest 106 corresponding to the spindle 103a is moved anddriven together with the tool 133 in the direction as shown by the arrowXE in FIG. 6 and in the directions as shown by the arrows XA and XB (Zaxis direction) in FIG. 5 appropriately. During the machining, aworkpiece 131 to be machined next is supplied by the hand 119 of theloading apparatus 109A as shown in FIG. 12.

In this way, as shown at the left in FIG. 13, when the first routine isperformed toward the workpiece 131, the spindle stock 103 is moved apredetermined distance together with the chuck 103b in the direction asshown by the arrow XB. At the same time, the spindle stock 105 is moveda predetermined distance in the direction as shown by the arrow XA withthe chuck 105b in an open stare. By this, the spindle stocks 103 and 105become close to each other. Then the right end portion of the workpiece131, which is held by the chuck 103b, and to which the first routinefinished in FIG. 14, is inserted in to the chuck 105b. The chuck 105 isthen closed and the right end portion of the workpiece 131, as seen inthe figure, is held. The chuck 103b is opened to release the holdingrelation between the chuck 103b and the workpiece 131. In this state thespindle stock 103 is moved a predetermined distance together with thechuck 103b in the direction as shown by the arrow XA, as shown in FIG.15. The spindle stock 105 is moved a predetermined distance, with theworkpiece 131 held by the chuck 105b, in the direction as shown by thearrow XB, to finish the delivery of the workpiece 131 between thespindle stocks 103 and 105.

Thereafter the chuck 105b is rotated together with the workpiece 131,and a tool rest 106 corresponding to the spindle 105a is moved anddriven together with a tool 133 in the direction as shown by the arrowXE in FIG. 6 and in the directions as shown by the arrows XA and XB (Zaxis direction) in FIG. 5. In this way, a second routine of themachining is performed toward the workpiece 131 by means of a tool 133,as shown in FIG. 6. During this time, another workpiece 131 is suppliedto the chuck 103b of the spindle stock 103 by means of the loadingapparatus 109A in order to perform the first routine of the machining onthe workpiece 131, as shown in FIG. 15.

In this way, when the second routine of the machining is performed onthe workpiece 131 held by the chuck 105b, the arm turning cylinder 112of the loading apparatus 109B is driven to retract the rod 112a in thedirection as shown by the arrow XH. As a result, the arm 117 is movedtogether with the hand 119 in the direction as shown by the arrow XK toposition the hand at the workpiece delivery position XX4 facing thechuck 105b, as shown in FIG. 17. In this state, the spindle stock 105 ismoved and driven in the direction as shown by the arrow XA such that theworkpicce 131, after the machining, is held by the chuck 105b. Theworkpiece 131 is then positioned at a position between the clamps 125aand 125b of the hand 119, and the clamps 125a and 125b are closed tohold the workpiece 131. Next, the holding relation between the workpiece131 and the chuck 105b is released. In this state, the spindle stock 105is moved together with the chuck 105b in the direction as shown by thearrow XB. The hand 119 is then turned and driven, together with theworkpiece 131 and after the machining, in the direction as shown by thearrow XL in FIG. 7, to position the hand of the waiting position XX3, asshown in full lines in FIG. 6. In this state, the holding relationbetween the workpiece 131 and the hand 119 of the loading apparatus 109Bis released, and the workpiece 131 is detached from the hand 119.

In the above-described embodiment, when the delivery of the workpiece131 between the spindle stocks 103 and 105 is performed, it had beenmentioned that the spindle stock 103 is moved in the direction as shownby the arrow XB, and the spindle stock 105 is moved in the direction asshown by the arrow XA, respectively, so that the spindle stocks 103 and105 approach each other. However, this method of approach of the twospindle stocks 103 and 105 is not critical. Any method of approach isavailable as long as these spindle stocks 103 and 105 are able toapproach each other without inconvenience. For example, it may be thatspindle stocks 103 and 105 approach each other to perform the deliveryof the workpiece 131 such that only the spindle stock 105 is movedtoward the spindle stock 103 in the direction as shown by the arrow XA,and the spindle stock 103 is not moved in the Z axis directions(directions as shown by the arrows XA and XB). On the contrary, it maybe that the spindle stocks 103 and 105 approach each other such that thespindle stock 103 only is moved toward the spindle stock 105 in thedirection as shown by the arrow XB, and the spindle stock 105 is notmoved in the Z axis directions.

In particular, in the case of the machining of a long-sized workpiece131, the loading apparatus 109A and 109B are positioned at waitingpositions XX1 and XX3 to adjust each hand 119, as shown in FIG. 18. Inthis state, the workpiece 131 is held by both the hands 119 and 119. Thespindle stock 103 is moved in the direction as shown by the arrow XA andthe spindle stock 105 is moved in the direction as shown by the arrow XBso as to be able to supply the workpiece 131 between the chucks 103b and105b. The interval between the chucks 103b and 105b is made wider, bythe predetermined distance, than the length of the workpiece 131 in thedirections as shown by the arrows XA and XB. Next, in this state, eacharm 117 of the loading apparatus 109A and 109B, as shown in FIG. 7, issynchronously turned and driven together with the hands 119 in thedirection as shown by the arrow XK.

The hands 119 are then positioned at a position facing each chuck 103band 105b of the spindle stocks 103 and 105, as shown in FIG. 19. Theworkpiece 131, which is held by the hands 119, is thus positionedbetween the chucks 103b and 105b. In this state, the spindle stock 103is moved together with the chuck 103b in the direction as shown by thearrow XB and the spindle 105 is moved together with the chuck 105b inthe direction as shown by the arrow XA. The workpiece 131 is then heldby being gripped by the chucks 103b and 105b. Next, the clamps 125a and125b of each hand 119 of the loading apparatus 109A and 109B are openedto release the holding relation between the hands 119 and the workpiece131. Furthermore, in this state, both arms 117 of the loading apparatus109A and 109B, as shown in FIG. 7, are turned and driven together withthe hands 119 in the direction as shown by the arrow XL to be returnedto the waiting positions XX1 and XX3, as shown in FIG. 18.

In this way, when the long-sized workpiece 131 is held by the chucks103b and 105b, the chucks 103b and 105b are synchronously rotatedtogether with the workpiece 131. Next, in this state, the tool rests106, as shown in FIG. 6, are moved and driven in the directions as shownby the arrows XE and XF and the arrows XA and XB as shown in FIG. 5 tomachine the workpiece 131 in a predetermined shape by a tool 133, suchas a bit, which is installed in each tool rest 106 as shown in FIG. 20.

When the long-sized workpiece 131 is machined in the predetermined shapeas shown in FIG. 21, the workpiece 131, after the machining, is held byeach hand 119 of the loading apparatus 109A and 109B, as shown in FIG.22. Furthermore, in this state the spindle stock 103 is moved in thedirection as shown by the arrow XA and the spindle stock 105 is moved inthe direction as shown by the arrow XB to retract from the workpiece131. Next, each hand 119 of the loading apparatus 109A and 109B aresynchronously turned and driven together with the workpiece 131 in thedirection as shown by the arrow XL, as shown in FIG. 7, to position theworkpiece 131 at the waiting positions XX1 and XX3 as shown in FIG. 23.In this state the holding relation between each hand 119 and theworkpiece 131 is released, and the workpiece 131 is carried to apredetermined location by removing the workpiece 131.

In the above-described embodiment, it has been mentioned that the clamps125a and 125b have workpiece holding portions 125c formed in a V-shape,are free to open, close and drive with the hand 119, as shown in FIG. 7,and the workpiece 131 is held by being gripped between each workpieceholding portion 125c of the clamps 125a and 125b. Of course, thisspecific structure is not critical; any appropriate structure isavailable if the hand 119 can surely hold the workpiece 131. Forexample, it may be that rollers are rotatably provided as the hand 119at the front edge portion of the clamp, as shown in FIG. 24.Hereinafter, the hand 119 having rollers will be explained on the basisof FIG. 24.

The hand 119 has a main body 137 which is provided at a top portion ofthe arm 117, as shown in FIG. 24. In the main body 137, a drivingcylinder 139 is provided. A rod 139a is supported on the drivingcylinder 139 so as to be free to project and recede in the right andleft directions in the figure, that is, in the directions as shown bythe arrows XP and XQ. At the top portion of the rod 139a is installed anengaging member 140. At the engaging member 140 is formed a slot 140a.In the slot 140a, rollers 141k, 141m, which are rotatably supported bytwo clamps 141a, 141b as described later, are fitted so as to be free toslide and engage with the slot 140a. The clamps 141a and 141b are freeto turn on the main body 137 through pin connections 141c and 141d inthe directions as shown by arrows XR and XS. At each top portion of theclamps 141a and 141b are rotatably provided rollers 141e and 141f onpins 141h and 141i. A roller 141g is rotatably disposed on the main body137, as shown in FIG. 24, by a pin 141j. The left edge portion of theroller 141g in the figure is projected from the main body 117 in thedirection as shown by an arrow XP.

A barfeeder machining operation is able to be performed on a workpiece131, which is a bar-shaped workpiece, making use of the loadingapparatus 109A and 109b having the hands 119 as described before and thebarfeeders 143 disposed at the right and left sides of the complexmachining machine tool 100 in FIG. 5.

When performing a barfeeder machining operation, at first the spindlestocks 103 and 105 as shown in FIG. 5 are moved and driven in thedirections a shown by the arrows XA and XB, respectively. The chuck 103bis positioned at the predetermined distance from the hand 119 of theloading apparatus 109A in the direction as shown by the arrow XA.Similarly, the chuck 105b is positioned at the predetermined distancefrom the hand 119 of the loading apparatus 109B in the direction asshown by the arrow XB. In this state, the barfeeders 143 as shown inFIG. 5 are driven to deliver workpieces 131 to the chucks 103b and 105bthrough each of spindles 103a and 105a. The workpieces 131 project theirrespective ends a predetermined length from the chuck 103b in thedirection as shown by the arrow XB and a predetermined length the chuck105b in the direction as shown by the arrow XA.

Next, the spindles 103a and 105a are rotated and driven, respectively,to rotate the workpieces 131 with the chucks 103b and 105b. At the sametime, each tool rest 106, as shown in FIG. 6, is moved and driventogether with the tool 133 in the direction as shown by the arrows XAand XB, and in the direction as shown by the arrows XE and XF, tomachine the outside cylindrical portions of the workpieces 131, as shownin FIG. 5.

At the time that the machining of the workpieces 131 is finished, theworkpieces 131 are cut off, such that the machined portion of theworkpieces 131 are apart from the other raw portions. To do this, atfirst the spindle stock 103 is moved together with the workpiece 131 inthe directions as shown by the arrows XA and XB and the spindle stock105 is moved together with the workpiece 131 in the directions as shownby the arrows XA and XB. Thereafter, each machined portion of theworkpieces 131 is positioned at a position facing each respective hand119 of the loading apparatus 109A and 109B. Each tool rest 106, as shownin FIG. 6, is moved and driven together with the cutting-off tool 133 inthe direction perpendicular to the paper surface of the figure, that is,in the direction as shown by the arrows XA and XB in FIG. 5, to positioneach tool 133 at a position facing the portion of the workpieces 131 tobe cut.

Next, the driving cylinder 139 of each hand 119, as shown in FIG. 24, isdriven to project the rods 139a together with the engaging members 140in the direction as shown by the arrow XP, respectively. Then the clamps141a and 141b of the hands 119 turn in the directions as shown by thearrows XS and are opened, with the pins 141c and 141d as their centers,because of the rollers 141k and 141m and the slot 140a of the engagingmember 140 being pushed by the rod 139a.

Each arm 117 of the loading apparatus 109A and 109B is then turned anddriven together with the hands 119 in the direction as shown by thearrow XK to make each machined portion of the workpieces 131, as shownin FIG. 5, fit in and engage between the clamps 141a and 141b of eachhand 119. The driving cylinder 139 of each hand 119, as shown in FIG.24, is driven to make each rod 139a, together with its engaging member140, retract in the direction as shown by the arrow XQ. Then the clamps141a and 141b turn, with the pins 141c and 141d as their center, eachroller 141k and 141m and the slot 140a of the engaging member 140 beingpulled by the rod 139a in the direction as shown by the arrow XR. Eachroller 141e and 141f of the clamps 141a and 141b then connects with thetop end portion of the respective workpieces 131. Furthermore, eachworkpiece 131 is pushed toward the roller 141g to be gripped between therollers 141e, 141f and 141g.

In this way, when each machined portion of the workpieces 131 issupported by its respective hand 119, the spindles 103a and 105a, asshown in FIG. 5, are rotated and driven together with the workpieces131. At the same time, the tool rests 106 are fed, together with thecutting-off tools 133, in the direction as shown by the arrow XE in FIG.6 to cut off the workpieces 131, so that each machined portion of theworkpieces 131 is separated from the remaining raw portion. Since theworkpieces 131 are rotatably supported by the rollers 141e, 141f and141g of each hand 119 as shown in FIG. 24, the hands 119 do not preventthe rotation of the spindles 103a and 105a, and the cutting-offoperation of each workpiece 131 is performed without inconvenience. And,since the machined portion of each workpiece 131 is supported by thehand 119 in such a manner that the movement in the directions as shownby the arrows XA and the XB is restricted, the machined portion does notfall from the hand 119.

When the machined portion of each workpiece 131 is cut off, each arm 117of the loading apparatus 109A and 109B, as shown in FIG. 24, is turnedand driven in the direction as shown by the arrow XL such that themachined portions of the workpieces 131 are supported with the hands119, and the hands 119 are positioned at the waiting positions XX1 andXX3, as shown in FIG. 6. Next, the clamps 141a and 141b of each hand 119of the loading apparatus 109A and 109B is opened. The supportingrelation between the hands 119 and the machined portion of theworkpieces 131 is then released. The machined portion is then removedfrom each hand 119 and carried to some predetermined location.

When the machined portion of each workpiece 131 is taken away, the barfeeders 143 as shown in FIG. 5, are driven. Thereafter, the workpieces131 are supplied to the chucks 103b and 105b through the spindles 103aand 105a to continue the predetermined barfeeder machining.

In the above-described embodiment, there had been mentioned the casewhere the workpiece 131, after the first routine, and being held by thechuck 103b, is delivered to the side of the spindle stock 105 such thatthe spindle stocks 103 and 105 approach each other by moving in the Zaxis direction.

However, in the method of delivery of the workpiece 131, the above caseis not critical. Any method is available if the workpiece 131 is able tobe surely delivered from the side of the spindle stock 103 to the sideof the spindle stock 105. For example, when the workpiece 131 is abar-shaped workpiece, and the machining is performed while the workpiece131 is supplied to the chuck 103b by the barfeeder 143, as shown on theleft hand side in FIG. 5, the holding relation between the workpiece 131and the chuck 103b is released after the first routine. In this statethe barfeeder 143 is driven to move the workpiece 131 in the directionas shown by the arrow XB. The end portion of the workpiece 131 is theninserted in chuck 105b. In this state the workpiece 131 is held by thechucks 103b and 105b in such a manner that the chucks 103b and 105b areclosed. The predetermined portion of the workpiece 131 between thechucks 103b and 105b is then cut off by cutting-off tool 133, asdescribed before, and the machining of the second routine is performedon the workpiece 131 held by the chuck 105b after the cutting.Furthermore, the workpiece 131 after the second routine is removed andcarried to the predetermined location from the chuck 105b, making use ofthe hand 119 of the loading apparatus 109B.

The delivery of the workpiece 131 may also be performed as follows.After the first routine, the holding relation between the chuck 103b andthe workpiece 131 is released. The workpiece 131 is then held by thehand 119 of the loading apparatus 109B. Furthermore, in this state, thespindle stock 103 is moved in the direction as shown by the arrow XA inFIG. 5 to pull the raw portion of the workpiece 131 out of the chuck103b. Next, the holding relation between the workpiece 131 and the hand119 is released. The spindle 105 is then moved in the direction as shownby the arrow XA. The top edge portion of the workpiece 131 is held bythe chuck 105b to cut off the workpiece 131. In this way the method ofthe delivery of the workpiece 131 is completed.

Another embodiment of a complex machining machine tool will be describedin FIG. 25 through FIG. 70.

A complex machining machine tool 201 has a machine body 202 as shown inFIG. 25. On the machine body 202, spindle stocks 203 and 205 mutuallyoppose each other. The spindle stocks 203 and 205 are movably anddrivably provided on guide rails 202a, as shown in FIG. 27, in thedirections as shown by arrows A₁ and B₁ (that is, in the W₁ axisdirection) and in the direction as shown by arrows A₂ and B₂ (that is,in the W₂ axis direction). Each direction is parallel to the directionas shown by arrows YA and YB. Spindles 203a and 205a are rotatably anddrivably provided on the spindle stocks 203 and 205 in the directions asshown by arrows YS and YT, as shown in FIG. 24, respectively. Chucks203b and 205b are installed on the spindles 203a and 205a. Through holes203c and 205c are formed in the spindles 203a and 205a penetrating thespindles 203a and 205 a in the directions as shown by arrows YA and YB.In the through holes 203c and 205c of the spindles 203a and 205a andchucks 203b and 205b are movably disposed centers 240 in the directionsas shown by the arrows YA and YB, as shown in FIG. 27.

On the machine body 202 are carriages 207, comprising tool rests 206Aand 206B, movably provided on guide rails 202c and disposed at rightangles to the paper surface in FIG. 26 (that is, the directions as shownby the arrows YA and YB in FIG. 27) in the directions as shown by thearrows A₃ and B₃ (that is, in the Z₁ axis direction) and in thedirection as shown by the arrow A₄ and B₄ (that is, in the Z₂ axisdirection). Each direction is parallel to the direction shown by thearrows YA and YB. With each carriage 207 of the tool rests 206A and 206Bis provided a respective ball screw 202b and 202d in the elongateddirections shown by the arrows YA and YB in FIG. 28. Each ball screw isconnected by a nut (not shown) to a respective carriage. Servo-motors(not shown) are connected with the ball screws 202b and 202d. The toolrests 206A and 206B move in respective movement areas ARE1 and ARE2, andthe servo-motors are driven to make the ball screws 202b and 202d rotatein reciprocal directions. The movement areas ARE1 and ARE2 denotemovement boundaries of each tool 233 in the directions as shown by thearrows YA and YB when the tool rests 206A and 206B move together withtheir tools 233 along the movement direction of the spindles 203 and205, that is, the directions as shown by the arrows YA and YB. Themovement areas ARE1 and ARE2 are provided so as to overlap. The commonmovement area ARE3 denotes the area of overlap of the movement areasARE1 and ARE2.

Furthermore, a turret base 209 is movably and drivably provided witheach carriage 207 on each of guide rails 202g in the directions as shownby the arrows C₁ and D₁ (in the X₁ axis direction) and in the directionsas shown by the arrows C₂ and D₂ (in the X₂ axis direction) as shown inFIG. 27. Each turret base 209 has a main body 210. With each main body210 is provided a turret 216 free to turn and drive in the directions asshown by arrows YJ and YK in FIG. 29. The turret 216 has a turret base217.

In the casing 217 and the turret base 209 is provided a tool rotationdriving structure 232. The tool rotation driving structure 232 has adriving motor 211, pulleys 211a and 213a, bearing portions 212 and 217b,a shaft 213, a belt 215, bevel gears 213b and 219a, and a rotation shaft219. In the main body 210 of the turret base 209 is disposed the drivingmotor 211. A shaft 211b is rotatably supported by the driving motor 211in the directions as shown by arrows YE and YF. The pulley 211a isinstalled on the shaft 211b. In the main body 210 is also provided thebearing portion 212. At the bearing portion 212, the shaft 213 extendsits shaft center YCT1 in the up and down directions in FIG. 29, that is,the directions as shown by arrows YG and YH, and is rotatably supported,with the shaft center YCT1 as its center, in the directions as shown byarrows YJ and YK. On the lower end portion of the shaft 213 is installedthe pulley 213a. The belt 215 is disposed to stretch between the pulley213a and the pulley 211a, which is installed on the shaft 211b of thedriving motor 211. At the upper end portion of the shaft is installedthe bevel gear 213b.

The turret 216 is rotatably disposed with the shaft 213 as its center inthe directions as shown by the arrows YJ and YK at the main body 210 ofthe turret base 209, as shown in FIG. 29. In the casing 217 of theturret 216 is provided a bearing portion 217b. In the bearing portion217b, the bevel gear 213b, which is installed on the shaft 213, isfitted to be free to rotate through a bearing 237a in the directions asshown by the arrows YJ and YK. The bevel gear 219a is rotatablysupported by the bearing portion 217b through a bearing 237b in thedirections as shown by arrows YL and YM.

In the bevel gear 219a is provided a hole 219c penetrating therethroughin the right and left directions in FIG. 30, that is, in the directionsas shown by arrows YP and YQ. In the hole 219c is disposed a key way219d. Furthermore, in the hole 219c of the bevel gear 219 is fitted therotation shaft 219, supported so as to be free to move only in thedirections as shown by the arrows YP and YQ and such that a key 219e,which is installed in the peripheral surface of the rotation shaft 219,is fitted in a key way 219d so as to be slidable. A right end portion219f of the rotation shaft 219 in FIG. 30 is provided with a pressuringportion 236a, which is composed of a clutch 236. The pressuring portion236a has a screw portion 219g, a nut 219h, a support pin 219i, and aspring 219j. The screw portion 219g is disposed at the right end portion219f of the rotation shaft 219.

The nut 219h is disposed at the screw portion 219g. Furthermore, in thecasing 217 of the turret 216 the support pin 219i is rotatably mountedby a bearing 219k to be rotatable in the directions as shown by arrowsYL and YM, thus facing the nut 219h. The spring 219j is disposed betweenthe nut 219h and the support pin 219i. At the left end portion of therotation shaft 219 in FIG. 30 is a wedge shaped connecting slot or hole219b, acting as part of the clutch 236.

Plural tool installation portions 217a are formed at the outsidesurfaces of the turrets 216, these surfaces being composed of the toolrests 206A and 206B, respectively. Workpiece center rest apparatus 220Aand 220B are installed on respective tool installation portions 217a.

Each workpiece center rest apparatus has a main body 221, as shown inFIG. 30. In the main body 221, a connecting shaft 222 is rotatablydisposed by a bearing 237c to be rotatable in the directions as shown bythe arrows YL and YM. At the right end portion of the connecting shaft222 is a wedge shaped connecting portion 222c also acting as part of theclutch 236. The connecting portion 222c is fitted in the connecting hole219b of the rotation shaft 219 so as to be free to connect and separate.A male screw 222b is disposed at a left end portion 222a of theconnecting shaft 222. An engaging member 223 is movably disposed on theleft edge portion 222a movable only in the directions as shown by thearrows YP and YQ, and such that a female screw 223b on the engagingmember 223 is fitted on the male screw 222b. A space 223a is formed onthe engaging member 223 in a ring shape surrounding the left edgeportion 222a of the connecting shaft 222.

Clamps 225 and 226 are disposed on the main body 221 to be free to openand close, pivoting on pins 225a and 226a in the directions as shown byarrows YR and YS. Each clamp is substantially L-shaped. Support rollers225b and 226b are rotatably mounted on the left end portions ofrespective clamps 225 and 226 on shafts 225d and 226d. Respective balls225c and 226c are provided on the other end portions of the clamps 225and 226. The balls 225c and 226c slidably fit in the space 223a of theengaging member 223. Furthermore, on the main body 221 between theclamps 225 and 226, a pressing roller 227 projects a portion thereof outof the main body 221, being rotatably disposed on a central shaft 227a.

With the above-described arrangement of the complex machining machinetool 201, when a long size shaft-shaped workpiece is required to bemachined with the machine tool 201, it is necessary for the workpiece230 to be supported by the workpiece center rest apparatus 220A or 220Bso as not to deflect the workpiece from the rotation center during themachining. To do this, the workpiece center rest apparatus 220A and 220Bare first installed in the turrets 216 of the tool rests 206A and 206B,as shown in FIG. 30, respectively. Each machine body 221 of theworkpiece center rest apparatus 220A and 220B are attached to a toolinstallation portion 217a of a turret 216 such that the connectingportion 222c of the connecting shaft 222 is fitted in the connectinghole 219b of the rotation shaft 219. The connecting shaft 222 is thensecurely connected with the rotation shaft 219, since the connectinghole 219b is pushed into the connecting portion 222c by the elasticityof the spring 219j.

At the time that the workpiece center rest apparatus 220A and 220B areinstalled in the turrets 216 of the tool rests 206A and 206B, apre-machining is performed. The pre-machining denotes the machiningbefore the main machining of a holding portion of the long-sizedworkpiece 230 for the chucks 203b and 205b (that is, both right and leftend portions 230f and 230e in FIG. 32), i.e. a cut in the form of acylinder, or a center hole 230i or 230j provided on end surfaces 230g or230h of the workpiece 230, as shown in FIG. 32 and FIG. 34.

The end portion 230f on the left side in the figure of the long-sizedworkpiece 230 to be machined, as shown in FIG. 32, is then held by thechuck 203b. Thereafter, the turret 216 of the tool rest 206A is turnedin the directions as shown by the arrows YJ and YK to make the workpiececenter rest apparatus 220A face the workpiece 230, as shown in FIG. 30.Next, the tool rest 206A is moved a predetermined distance, togetherwith the workpiece center rest apparatus 220A, in the direction of arrowC₁ in FIG. 27, that is, in the direction of arrow YP in FIG. 30, and theworkpiece 230 is passed between the rollers 225b and 226b. In this way,the pressing roller 227 of the center rest apparatus 220A comes intocontact with the workpiece 230.

The driving motor 211 in the turret base 209, as shown in FIG. 29, isthen driven to rotate the pulley 211a in the direction as shown by thearrow YF. The shaft 213 rotates together with the bevel gear 213b,through the pulleys 211a and 213a and the belt 215, in the direction asshown by the arrow YK. The rotation shaft 219 rotates due to the bevelgears 213b and 219a in the direction as shown by the arrow YL.Accordingly, the connecting shaft 222, as shown in FIG. 30, rotates bythe connecting hole 219b and the connecting portion 222c in thedirection as shown by the arrow YL, and the left end portion 222a of theconnecting shaft 222 also rotates in the direction as shown by the arrowYL. When a torque greater than a predetermined torque value istransmitted to the connecting shaft 222 through the clutch 236, theconnection between the connecting hole 219b of the clutch 236 and theconnecting portion 222c is released. The connecting shaft 222 thus stopsrotating in the direction as shown by the arrow YL.

After the connecting shaft 222 rotates in the direction as shown by thearrow YL, the engaging member 223, which is fitted on the male screw222b of the left end portion 222a by the female screw 223b, moves towardthe shaft center YCT1 of the shaft 213 in the direction as shown by thearrow YQ in FIG. 30. The balls 225c and 226c of the clamps 225 and 226then turn on their pins 225a and 226a in the direction shown by thearrow YS, being pulled by the engaging member 223, the balls 225c and226c slidably moving in the space 223a of the engaging member 223. Eachsupport roller 225b and 226b of the clamps 225 and 226 then also turnsin the direction as shown by the arrow YS, as shown in FIG. 31, to comeinto contact with the workpiece 230. Furthermore, the workpiece 230 ispressed by the pressing roller 227.

At this point the pressuring support force operating on the workpiece230 depends on the torque which is transmitted to the connecting shaft222 from the rotation shaft 219 through the clutch 236, as shown in FIG.30. If the transmission torque is more than a certain value, theconnection between the connecting hole 219b and the connecting portion222c is released against the elasticity of the spring 219j. Accordingly,the connecting shaft 222 then stops rotating in the direction as shownby the arrow YL. The torque then is no longer transmitted to the clamps225 and 226 through the engaging member 223, and the clamps 225 and 226stop turning in the direction shown by the arrow YS. As a result, thesupport rollers 225b and 226b stop pressing the workpiece 230 againstthe pressing roller 227, and the pressuring support force operating onthe workpiece 230 is maintained at the set value. Accordingly, theworkpiece 230 will not become difficult to rotate, since it is notpressed too much by the center rest apparatus 220A and 220B.

After the workpiece 239 is supported by the workpiece center restapparatus 220A, held by the support rollers 225b and 226b and thepressing roller 227, the turret 216 of the tool rest 206B, as shown inFIG. 26, is turned in the direction as shown by the arrows YJ and YK toposition a tool 233 for machining a center hole ar a predeterminedposition. Thereafter, the ball screw 202d, as shown in FIG. 28, isrotated by driving the servo-motor (not shown). The tool rest 206B isthen moved together with the tool 233 in the direction as shown by thearrow A₄ in FIG. 32. Moreover, the tool rest 206B is moved apredetermined distance in the direction as shown by the arrow C₂. Thenthe tool 233 is positioned at the position facing the end surface 230gof the right side of the workpiece 230. Next, the chuck 203b is rotatedtogether with the workpiece 230 in the direction as shown by the arrowYS. In this state the tool rest 206B is fed a predetermined distancetogether with the tool 233 in the direction as shown by the arrow A₄.The center hole 230i is then formed at the end surface 230g of theworkpiece 230 by means of the tool 233.

Since the workpiece 230 is supported near the end portion 230e on theright side in FIG. 32 with the workpiece center rest apparatus 220A, theworkpiece 230 does not deflect from the rotation center during machiningof the center hole 230i, and the center hole 230i is formed smoothly.

After the center hole 230i is formed, the tool rest 206B is moved in thedirection as shown by the arrow B₄ and in the direction as shown by thearrow D₂, as shown in FIG. 32, to move and retract from the workpiece230. Next, the turret 216 of the tool rest 206B is turned in thedirection as shown by the arrows YJ and YK to position the tool 233 forcutting the outside cylindrical portion at the predetermined position.The tool rest 206B is moved and driven, together with the tool 233 forcutting the cylindrical portion, in the directions as shown by thearrows A₄ and B₄ and in the directions as shown by the arrows C₂ and D₂.The edge portion 230e of the workpiece 230 is then cut in the form of acylinder by making use of the tool 233. Since the workpiece 230 isrotatably supported near the edge portion 230e on the right side in FIG.32 with the workpiece center rest apparatus 220A, similar to theprovision of the center hole 230i described above, the workpiece 230does not deflect from the rotation center during the machining, and thecutting of the cylinder portion is accurately performed. After themachining is finished, the tool rest 206B is moved and retracted in thedirection as shown by the arrow B₄ and in the direction as shown by thearrow D₂.

Thereafter, the chuck 205b of the spindle stock 205, as shown in FIG.32, is opened. The spindle stock 205 is moved in the direction as shownby the arrow A₂. The machined end portion 230e on the right side in thefigure of the workpiece 230 is inserted in the chuck 205b, as shown inFIG. 33. Next, the chuck 205b is closed. Furthermore, the driving motor211 of the tool rotation driving structure 232 as shown in FIG. 29 isdriven to release the supporting relation between the workpiece centerrest apparatus 220A and the workpiece 230. The shaft 211b is rotated inthe direction as shown by the arrow YE. Then the connecting shaft 222 ismoved, through the pulleys 211a and 213a, the belt 215, the shaft 213,the bevel gears 213b and 219a, the rotation shaft 219, and the clutch236, in the direction as shown by the arrow YM. The engaging member 223as shown in FIG. 30 is then moved in the direction as shown by the arrowYP. The clamps 225 and 226 are turned about the pins 225a and 226athrough the balls 225c and 226c in the direction shown by the arrow YR,so that the support rollers 225b and 226b move apart from the workpiece230. Accordingly, the supporting relation between the workpiece centerrest apparatus 220A and the workpiece 230 is released. After thesupporting relation between the center rest apparatus 220A and theworkpiece 230 is released, the tool rest 206A is moved in the directionas shown by the arrow D₁ in FIG. 32 to retract from the workpiece 230.

Thereafter, the spindle stock 203 is moved in the direction as shown bythe arrow B₁, and at the same time the spindle stock 205 is moved in thedirection as shown by the arrow B₂. The spindle stocks 203 and 205 arethen synchronously moved a predetermined distance together with theworkpiece 230 in the direction as shown by the arrow YB. Next, theturret 216 of the tool rest 206B as shown in FIG. 26 is turned in thedirection as shown by the arrows YJ and YK to position the workpiececenter rest apparatus 230. Moreover, in this state the tool rest 206B ismoved together with the workpiece center rest apparatus 220B in thedirections as shown by the arrows A₄ and B₄ and in the direction asshown by the arrow C₂ in FIG. 34. Near the end portion 230f on the leftside in the figure the workpiece 230 is supported by the center restapparatus 220B.

Thereafter, the chuck 203b of the spindle stock 203 is opened. Thespindle stock 203 is moved in the direction as shown by the arrow A₁ toposition the spindle stock 203 at the position as shown by full lines inFIG. 34. The turret 216 of the tool rest 206A is turned in thedirections as shown by the arrows YJ and YK to position a tool 233 formachining the center hole ar a predetermined position. Furthermore, theservo-motor (not shown) is driven so that the ball screw 202b, as shownin FIG. 28, is rotated. The tool rest 206A is then moved thepredetermined distance together with the tool 233 in the directions asshown by the arrows A₃ and B₃ in FIG. 34 and in the direction shown bythe arrow C₁. Then the tool 233 for machining the center hole ispositioned at a position facing the end portion 230h of the workpiece230.

Next, the chuck 205b is rotated together with the workpiece 230 in thedirection as shown by the arrow YS. The tool rest 206A is fed thepredetermined distance together with the tool 233 for machining thecenter hole in the direction as shown by the arrow B₃, forming thecenter hole 230j at the end surface 230h of the workpiece 230 with thetool 233. After the center hole 230j is formed on the workpiece 230, theturret 216 of the tool rest 206A is turned in the directions as shown bythe arrows YJ and YK to position the tool 233 for cutting the outsidecylindrical portion at a predetermined position. In this way, the edgeportion 230f of the workpiece 230 is cut in the form of a cylinder bythe tool 233.

Since the workpiece 230 is supported near its end portion 230f by thecenter rest apparatus 220B. The workpiece 230 does not deflect from itsrotation center. This enables the center hole 230j to be accuratelyformed on the workpiece 230, and the outside cylindrical portion of theedge portion 230f can also be accurately machined. After the machining,the tool rest 206A is moved and retracted in the direction as shown bythe arrow D₁.

After the pre-machining of the workpiece 230 is finished, the chuck 203bis opened. In this state the tool rest 203 is moved a predetermineddistance together with the chuck 203b in the direction as shown by thearrow B₁. The end portion 230f of the workpiece 230 is inserted in thechuck 203b. The chuck 203b is then closed. The workpiece 230 is thusheld between the chucks 203b and 205b as shown in FIG. 35. Then, theworkpiece 230 is positioned at a position corresponding to the commonmovement area ARE3 as shown in FIG. 28. Thereafter the supportingrelation between the workpiece center rest apparatus 220B and theworkpiece 230 is released. The chucks 203b and 205b are synchronouslyrotated in the direction as shown by the arrow YS. The tool rest 206A isthen moved together with the tool 233 for cutting the outsidecylindrical portion in the directions as shown by the arrows C₁ and D₁and in the directions as shown by the arrows A₃ and B.sub. 3, in themovement area as shown in FIG. 28. In this way, the main machining isperformed on the outside cylindrical portion of the workpiece 230 inFIG. 35 by the tool 233 installed on tool rest 206A. Since the longsized workpiece 230 is positioned at the position corresponding to thecommon movement area ARE3 by the spindle stocks 203 and 205, as shown inFIG. 28, the main machining can be also performed on the workpiece 230by the other tool rest 206B. That is, the tool rest 206B is movedtogether with the tool 233 for cutting the outside cylindrical portionin the directions as shown by the arrows C₂ and D₂, and in thedirections as shown by the arrows A₄ and B₄, in the movement area ARE2.In this way, the machining can also be performed on the portion of theworkpiece 230 between the chucks 203b and 205b by the tool 233 on thetool rest 206B.

Thereafter, the machining of the portion of the workpiece 230 which isheld by the chuck 205b, that is, the end portion 230e on the right sidein FIG. 36, is performed. For this purpose, the center 240, which isdisposed in the spindle stock 205, is moved a predetermined distance inthe direction as shown by the arrow YA in the spindle 205a and the chuck205b, as shown in FIG. 36. Then the center 240 projects out from thechuck 205b in the direction as shown by the arrow YA and is inserted inthe center hole 230i, which is disposed at the end portion 230g of theworkpiece 230.

Next, the holding relation between the chuck 205b and the workpiece 230is released. The spindle stock 205 is moved the predetermined distancetogether with the chuck 205b in the direction as shown by the arrow B₂.At the same time, the center 240 is moved, at the same speed as chuck205, in the direction as shown by the arrow A₂. The chuck 205b is thenpositioned at a position apart from the end portion 230e a predetermineddistance on the right side in FIG. 36, the end portion 203e of theworkpiece 230 being supported with the center 240. The chuck 203b isthen rotated together with the workpiece 230 in the direction as shownby the arrow YS. Furthermore, the machining is performed on the endportion 230e on the right side of the workpiece 230 in FIG. 36 with thetool 233, which is installed in the tool rest 206B, to machine the endportion of the workpiece. The workpiece 230 then does nor deflect fromits rotation center, because it is supported by the center 240, and themachining on the end portion 230e of the workpiece 230 is performedaccurately. After the machining, the center 240 is moved and retractedin the direction as shown by the arrow YB, and is positioned at theposition as shown by the broken line in FIG. 37. The end portion 230e,after the machining, is held by the chuck 205b.

At the same time, the center 240, provided in the spindle stock 203, isprojected from the position shown by the broken line in FIG. 36 throughthe spindle 203a and the chuck 203b a predetermined distance away fromthe chuck 203b in the direction as shown by the arrow YB for the purposeof machining the workpiece portion (that is, the end portion 230f of theworkpiece 230) being held by the chuck 203b, and is inserted in thecenter hole 230j of the workpiece 230 on the left side in the figure.The end portion 230f of the workpiece 230 is supported by the center240, and the chuck 203b is retracted to the left side in the figure, asshown in FIG. 37. In this state, the machining is performed toward theend portion 230f of the workpiece 230 on the left side in the figure bymeans of the tool 233 installed in the tool rest 206A. As describedbefore, the workpiece 230 does not deflect from its rotation centerbecause it is held by the center 240. Accordingly, the machining on theend portion 230f of the workpiece 230e is performed accurately.

Since the workpiece 230 being held between the spindle stocks 203 and205 is positioned at the position corresponding to the common movementarea ARE3 as shown, in FIG. 28, the machining can also be performed onthe end portion 230f of the workpiece 230 by means of the tool rest206B. That is, the tool rest 206A is moved and retracted in thedirection as shown by the arrow A₃. Secondly, the tool rest 206B ismoved, together with the tool 233 used for machining the end portion230e of the workpiece 230, in the direction as shown by the arrow A₄ inthe movement area ARE2. The tool 233 then faces the end portion 230f ofthe workpiece 230 as shown in FIG. 37. In this state the tool rest 206Bis fed the predetermined distance together with the tool 233 in thedirections as shown by the arrows A₄ and B₄. In this way, the machiningis performed on the end portion 230f of the workpiece 230, in the formof a cylinder, by means of the tool 233. In case the machining isperformed on the end portion 230f of the workpiece 230 by means of thetool rest 206B, the machining of end portions 230e and 230f of theworkpiece 230 can be performed by means of only the tool 233 installedon one tool rest (that is, the tool rest 206B in the presentembodiment). It is then not necessary to install the tool 233 for thepurpose of machining the end portions 230e and 230f of the workpiece 230on the other tool rest (the tool rest 206A in the present embodiment).

If a boring operation is performed on each end portion 230e and 230f ofthe workpiece 230, at first a pre-machining (exclusive of the machiningproviding the center holes 330i and 330j as shown in FIG. 32 and FIG.34), as shown in FIG. 32 through FIG. 34, is performed on the endportions 230e and 230f of the workpiece. Moreover, the main machining isperformed on the outside cylindrical portion of the workpiece 230 asshown in FIG. 35. Then the end portion 230e of the workpiece 230 on theright side in FIG. 38 is supported by the workpiece center restapparatus 220A, which is installed in the tool rest 206A.

Thereafter, the tool rest 206B is moved, together with a tool 233 suchas a drill or a boring tool, for cutting the inside diameter portion inthe directions as shown by the arrows A₄ and B₄ and in the direction asshown by the arrow C₂. The tool 233 faces the end surface 230g of theworkpiece 230. Next, the chuck 230b is rotated together with theworkpiece 230 in the direction as shown by the arrow YS. The tool rest206B is then fed the predetermined distance together with the tool 233to cut the inside diameter portion with the tool 233 to cut the insidediameter portion in the direction as shown by the arrow A₄. In this way,a predetermined machining of the inside diameter portion is performed onthe end portion 230e of the workpiece 230 by means of the tool 233. Theoutside cylindrical portion of the end portion 230e of the workpiece 230is also machined by means of the tool 233 installed on the tool rest206B. Since the workpiece 230 is supported near its end portion 230e bythe workpiece center rest apparatus 220A, the workpiece 230 does notdeflect from its rotation center, even when the cutting force of thetool 233 operates upon the workpiece 230. The machining of the insidediameter portion the outside cylindrical portion are then accuratelyperformed on the end portion 230e of the workpiece 230.

Thereafter, the spindle stock 205 as shown in FIG. 38 is moved apredetermined distance together with the chuck 205b in the direction asshown by the arrow A₂ to hold the end portion 230e of the workpiece 230with the chuck 205b. The supporting 220A and the workpiece 230 is thenreleased. In this state the tool rest 206A is moved and retracted in thedirection as shown by the arrow D₁. The spindle stocks 203 and 205 aresynchronously moved together with the workpiece 230 in the direction asshown by the arrow YB to position the spindle stock 205 at the positionas shown in FIG. 39. The end portion 230f of the workpiece 230 on theleft side in the figure is then supported by the workpiece center restapparatus 220B installed on the tool rest 206B. The holding relationbetween the spindle stock 203 and the workpiece 230 is subsequentlyreleased. Then the spindle stock 203 is moved the predetermined distanceaway from the workpiece 230 in the direction as shown by the arrow A₁ tothe position as shown by full lines in the figure.

Thereafter, the predetermined machining of the inside diameter portionis performed on the end portion 230f of the workpiece 230 by means ofthe tool 233 installed on the tool rest 206A for cutting the insidediameter portion. Moreover, a predetermined machining of the outsidecylindrical portion is performed on the end portion 230f of theworkpiece 230 by means of a tool (not shown) installed on the tool rest206A for machining the outside cylindrical portion. Since the workpiece230 is supported at its end portion 230f by the workpiece center restapparatus 220B, the workpiece 230 is able to be efficiently preventedfrom deflecting from its rotation center, even if the cutting force ofthe tool operates upon the workpiece 230.

In the above-described embodiment, when a shaft shaped workpiece isrequired to be machined it was mentioned that the workpiece 230 issupported by the centers 240. However, in supporting the workpiece thisfeature is not critical. Any method of support is available if the endportions 230e and 230f of the workpiece 230 can be rotatably supportedin the directions as shown by the arrows YS and YT when the machining isperformed. For example, face drivers 203d as shown in FIG. 40 can beinstalled in the spindles 203a and 205a of the spindle stocks 203 and205 as the workpiece supporting means. The workpiece 230 may be heldbetween the face drivers 203d, and a main machining operation may beperformed on the workpiece 230.

When a bar shaped workpiece is required to be machined the bar shapedworkpiece 230 is set to project an end portion thereof from the chuck203b a predetermined distance in the direction as shown by the arrow YBthrough the through hole 203c of the spindle 203a and the chuck 203b, asshown in FIG. 41. Secondly, the chuck 203b is rotated together with thebar shaped workpiece 230 in the direction as shown by the arrow YS. Inthis state, the machining of the end portion of the bar shaped workpiece230 is performed. Then the chuck 205b is opened and the spindle 205 ismoved a predetermined distance toward the spindle 203 in the directionas shown by the arrow A₂. The chuck 205b is then positioned at theposition as shown by the imaginary line in FIG. 41. The bar shapedworkpiece 220 is then held by both the chucks 203b and 205b by closingthe chuck 205b.

Thereafter, the holding relation between the chuck 203b and theworkpiece 230 is released. The spindle stock 204 is moved apredetermined distance together with the chuck 205b in the direction asshown by the arrow B₂. Then the bar shaped workpiece 230 is moved in thedirection as shown by the arrow YB so as to be pulled by the chuck 205b.The raw portion of the bar shaped workpiece 230 is pulled out from thechuck 203b to a predetermined length, as shown in FIG. 42, to positionthe workpiece to correspond to the common movement area ARE3 as shown inFIG. 28. Next, the chuck 203b is closed to hold the workpiece 230 withboth the chucks 203b and 205b. The chucks 203b and 205b are thensynchronously rotated together with the bar shaped workpiece 230 in thedirection as shown by the arrow YS. Thereafter, the tool rest 206A or206B is moved, together with a tool 233, in the direction as shown bythe arrows A₃ and B₃, or in the directions as shown by the arrows A₄ andB₄, respectively. In this way a predetermined machining is performed onthe bar shaped workpiece 230 between the chucks 203b and 205b by meansof the tool 233.

Thereafter the holding relation between the chuck 205b and the barshaped workpiece 230 is released. The spindle stock 205 is then moved apredetermined distance together with the chuck 205b in the direction asshown by the arrow A₂ in FIG. 43. The machined portion of the bar shapedworkpiece 230 is inserted into the through hole 205c of the spindlestock 205. Next, the chuck 205b is closed, and the machined portion ofthe bar shaped workpiece 230 is held. At the same time, the holdingrelation between the chuck 203b and the bar workpiece 230 is released.The spindle stock 205 is then moved a predetermined distance togetherwith the chuck 205b in the direction as shown by the arrow B₂, and thebar shaped workpiece 230 is moved in the direction as shown by the arrowYB, the raw portion of the bar workpiece 230 being pulled out from thechuck 203b.

Thereafter, a predetermined portion of the bar shaped workpiece 230between the chucks 203b and 205b is cut off. The spindle stock 205 isthen moved together with the chuck 205b in the direction as shown by thearrow B₂ in FIG. 43. Secondly, a machining is performed on the left endportion of a workpiece block 230c (that is, the machined portion of thebar shaped workpiece 230 which has been cut and separated from the barshaped workpiece 230) being held by the chuck 205b in FIG. 44. The rightend portion of the workpiece 230 in the figure, held by the chuck 203b,is also machined. At each spindle 203a and 205a of the spindle stocks203 and 205, the through holes 203c and 205c are formed to penetrate inthe directions as shown by the arrows YA and YB, as shown in FIG. 41.Therefore, successive machining operations can be performed on theoutside cylindrical portion of the workpiece 230 such that a long andbig workpiece 230 can be held by the chucks 203b and 205b through thethrough holes 203c and 205c. The workpiece pulling-out movement as shownin FIG. 41 through FIG. 43 is performed by the spindle stocks 203 and205 to pull out the raw portion of the workpiece 230 in the direction asshown by the arrow YB, and thus the raw portion of the workpiece 230 canbe machined at every movement.

If the bar shaped workpiece 230 is to be machined so as to cut out twokinds of workpieces, e.g. 230r and 230s, and the cut out workpieces 230rand 230s are to be screwed to each other, one combination part 230T canbe made. The bar shaped workpiece 230 is set projecting its end portion230d from the chuck 203b a predetermined distance and in the directionas shown by the arrow YB, through the spindle 203a and the chuck 203b,by means of a bar feeder 241 disposed at the left in FIG. 45.Thereafter, the chuck 203b, as shown in FIG. 46, is rotated at apredetermined rotating speed together with the bar shaped workpiece 230in the direction as shown by the arrow YS. A machining is then performedfor cutting the outside cylindrical portion of the end portion 230d ofthe bar shaped workpiece 230 by means of the tool 233 installed in thetool rest 206A. Furthermore, a male screw is formed on the end portion230d by means of a tool 233 for cutting threads.

The spindle stock 203 is then moved in the direction as shown by thearrow B₁, the bar shaped workpiece 230 being held by the chuck 203b. Thespindle stock 205 is moved a predetermined distance, together with thechuck 205b, toward the spindle stock 203 in the direction as shown bythe arrow A₂. Then the end portion 230d of the bar shaped workpiece 230is inserted inside the chuck 205b, as shown in FIG. 47. Next, the chuck205b is closed to hole the end portion 230d of the bar shaped workpiece230. The chucks 203b and 205b are then synchronously rotated togetherwith the bar shaped workpiece 230 in the direction as shown by the arrowYS. Under this condition, the predetermined portion of the bar workpiece230 being held between the chucks 203b and 205b is cut by means of thetool 233 installed in the tool rest 206A or 206B.

Thereafter, the spindle stock 203 is moved a predetermined distancetogether with the bar shaped workpiece 230 in the direction as shown bythe arrow A₁ in FIG. 47. The spindle stock 205 is then moved togetherwith a workpiece 230r (the workpiece 230r denotes the part of the barshaped workpiece 230 cut and separated from the bar shaped workpiece 230held by the spindle stock 203) in the direction as shown by the arrowB₂. In this way, the spindle stocks 203 and 205 are positioned at thepositions as shown in FIG. 48, respectively. Thereafter, a female screw230m is formed at the end portion 230d of the bar shaped workpiece 230being held by the spindle stock 203 by means of a tool 233 installed inthe tool rest 206A for cutting an interior cylindrical portion, such asa drill or boring tool, and a tool 233 for forming a female screw. Onthe other hand, a male screw 230n is formed by means of a tool 233installed in the tool rest 206B, forming a male screw on the raw portionof the workpiece 230r delivered to the spindle stock 205.

In this way the male screw 230n is formed on the workpiece 230r and thefemale screw 230m is formed on the end portion 230d of the bar shapedworkpiece 230. The chuck 205b, as shown in FIG. 48, is then rotatedtogether with the workpiece 230r with a predetermined rotational speed(usually a rotation of low speed) in the direction as shown by the arrowYS or in the direction as shown by the arrow YT. Thereafter, the spindlestock 205 is moved together with the workpiece 230r in the direction asshown by the arrow A₂. At the same time, the spindle stock 203 is movedtogether with the bar shaped workpiece 230 toward the spindle stock 205in the direction as shown by the arrow B₁. Then the male screw 230n ofthe workpiece 230r is also moved in the direction as shown by the arrowYA while rotating in the direction as shown by the arrow YS or YT, tofit in the female screw 230m of the bar shaped workpiece 230. Theworkpiece 230r is thus connected with the bar shaped workpiece 230.Next, the chucks 203b and 205b are synchronously rotated, together withthe connected workpieces 230r and 230, in the direction as shown by thearrow YS. A predetermined portion of the bar shaped workpiece 230 beingheld between the chucks 203b and 205b is then cut by means of acutting-off tool 233 installed on the tool rest 206B. Since the chucks203b and 205b synchronously rotate in the same direction, the bar shapedworkpiece 230 and the workpiece 230r held by the chucks 203b and 205bare also synchronously rotated in the same direction. Thereafter theassembly of the bar shaped workpiece 230 and the workpiece 230r do notloosen during the cutting-off machining.

The assembly of the workpiece 230r and a workpiece 230s (the workpiece230s denotes the portion of the bar shaped workpiece 230 which is fittedin the workpiece 230r and cut and separated from the the bar shapedworkpiece 230 held by the spindle stock 203) is performed in such amanner that the male screw 230n is fitted in the female screw 230m, andsuch that once a connecting part 230T, being composed of the workpieces230r and 230s, is made, the spindle stock 205 is moved a predetermineddistance together with the connecting part 230T in the direction asshown by the arrow B₂. The spindle stock 203 is moved a predetermineddistance together with the bar shaped workpiece 230 in the direction asshown by the arrow A₁. Thus the spindle stocks 203 and 205 arepositioned at the positions as shown in FIG. 50. The bar feeder 241, asshown at the left in the figure, is then driven, and the bar shapedworkpiece 230 is moved in the direction as shown by the arrow YB. Theend portion 230d of the bar shaped workpiece 230 is projected from thechuck 203b a predetermined length in the direction as shown by the arrowYB. A predetermined machining is then performed, by means of the tool233 installed on the tool rest 206A, on the end portion 230d of the barshaped workpiece 230. A machining of an end face is performed by meansof the tool 233 installed on the tool rest 206B on the workpiece 230s ofthe connecting part 230T being held by the spindle stock 205, as shownin FIG. 50, to finish the machining of the connecting part 230T.

In this way, at the time that the machining on the connecting part 230Thas finished, a parts catcher 242, installed on the tool rest 206B, ispositioned at a position separated from the chuck 205b with apredetermined distance in the direction as shown by the arrow YA, asshown in FIG. 51. The chuck 205b is then opened, and the connecting part230T is removed from the chuck 205b in the direction as shown by arrowYA by means of a well known workpiece removing device 245 disposed inthe spindle 205a, and the connecting part 230T is caught by the partscatcher 242 and is carried out of the machine.

In the above-described embodiment, the case is mentioned where differentkinds of workpieces 230r and 230s are cut off from the bar shapedworkpiece 230 and machined, and one connecting part 230T is made byassembling the workpieces 230r and 230s with the spindle stocks 203 and205. However, component parts of a connecting part 230T are notrestricted to the workpieces 230r and 230s cut-off from the same barshaped workpiece 230. Many workpieces are imaginable. For example, oneconnecting part 230T can also be made by different kinds of workpieces230A and 230B, of a single substance. As shown in FIG. 52, theworkpieces 230A and 230B are machined, and the assembly thereof isperformed. The first routine of the machining is performed on theworkpiece 230A, which is supplied by a workpiece handling unit 243,described hereinafter, by means of the tool 233 at the spindle stock203, to form a press-in portion 230v in the shape of a bar. The secondroutine of machining is performed on the workpiece 230B on the spindlestock 205 by means of the tool 233 after the first routine of themachining has been performed on the spindle stock 203. Thereafter, thespindle stock 203 is moved together with the chuck 203b in the directionas shown by the arrow B₁. At the same time, the spindle stock 205 ismoved together with the workpiece 230B in the direction as shown by thearrow A₂. Then the workpieces 230A and 230B approach each other, asshown in FIG. 53. The press-in portion 230v of the workpiece 230A ispressured into a hole 230w of the workpiece 230B. The assembly of theworkpieces 230A and 230B is thus performed, and the connecting part 230Tis made.

When the assembly of the two kinds of workpieces 230A and 230B isperformed to make the connecting part 230T, the holding relation betweenthe workpieces 230A and the chuck 203B is released. The spindle stock205 is then moved a predetermined distance together with the assembledworkpieces 230A and 230B in the direction as shown by the arrow B₂, to aposition as shown in FIG. 54. The spindle stock 203 is also moved apredetermined distance in the direction as shown by the arrow Al toposition it as shown in FIG. 54.

Thereafter, a second workpiece 230B is supplied to the spindle stock203, as shown in FIG. 54, by means of the workpiece handling unit 243,and the first routine of the machining is performed on the suppliedworkpiece 230B, as shown in FIG. 55. Thus the hole 230w and the like areformed. A second routine of the machining is performed on the workpiece230A of the connecting part 230T on the spindle stock 204. Next, theconnecting part 230T, which the machining has finished, is carried offthe machine from the spindle stock 205 by means of the workpiecehandling unit 243 as shown at the right side in FIG. 56.

Thereafter, the spindle stocks 203 and 205 are moved a predetermineddistance in the direction as shown by the arrow B₁ and in the directionas shown by the arrow A₂, as shown in FIG. 57, respectively. Theworkpiece 230B, after the first routine wherein it is held by thespindle stock 203, is delivered to the spindle stock 205. This deliveryof the workpiece 230B is usually performed with the chucks 203b and 205bstopped. However, the spindle stocks 203 and 205 approach each other ina spare wherein the spindles 203a and 205a of both spindle stocks 203and 205, that is, the chucks 203b and 205b, are rotated in order toshorten the machining time. Thereafter, the delivery movement can benaturally performed between both spindle stocks 203 and 205 while theworkpiece 230B is rotated. In this case, the workpiece 230B can bedelivered between the spindles 203a and 205a without generating a phaseshift, such that the phases of rotation of both spindles 203a and 205ain the C-axis direction match each other, even if a milling machiningaccompanied by C-axis control is performed on the workpiece 230B. Whenthe workpiece 230B is delivered to the spindle stock 205, the secondroutine of the machining is performed on the workpiece 230B, as shown inFIG. 58. A premachined workpiece 230A is supplied to the chuck 203b ofthe spindle stock 203 by means of the workpiece handling unit 243, tostart the first routine of the machining on the workpiece 230A. Then thepress-in portion 230v is formed.

In the above-described embodiment, it was mentioned that the connectingpart 230T was made in such a manner that different kinds of workpieceswere fitted and pressed-in to each other to assemble them. In the methodof assembly, this feature is not critical. Any method if available, if apair of workpieces can be surely connected such that the spindle stocks203 and 205 approach each other while holding the respective workpieces.

In a further case where workpieces machining is performed making use ofthe complex machining machine tool 201, the workpiece 230 to be machinedis supplied with the chuck 203b of the spindle stock 203 as shown inFIG. 59. The first routine of the machining is performed by means of thetool 233 on the workpiece 230. Secondly, the spindle stock 203 is movedtogether with the workpiece 230 toward the spindle stock 205 in thedirection as shown by the arrow B₁, as shown in FIG. 60. At the sametime, the spindle stock 205 is moved in the direction as shown by thearrow A₂ while opening the chuck 205b. The workpiece 230 is held by boththe chucks 203b and 205b after the chuck 205b is closed. Thereafter, theholding relation between the chuck 203b and the workpiece 230 isreleased. The spindle stock 203 is then moved in the direction as shownby the arrow A₁, and the spindle stock 205 is moved together with theworkpiece 230 in the direction as shown by the arrow B₂. Thus thespindle stocks 203 and 205 are positioned as shown in FIG. 61.

Thereafter, the second routine of the machining is performed on theworkpiece 230, which was delivered to the spindle stock 205, as shown inFIG. 61. At the spindle stock 203, the second routine of the machining,which is the same routine as the machining at the spindle stock 204, isperformed on a new workpiece 230, as shown in FIG. 62, after the rawworkpiece 230 has been supplied to the spindle stock 203. Thus the samemachining (that is, the second routine of the machining) is performed atnearly the same time at the spindle stocks 203 and 205. Therefore themachining finishing time is almost the same for both spindle stocks.After the machined workpiece 230 is removed from the chuck 205b, theworkpiece 230 held by the spindle stock 204, after the second routine ofthe machining, can be delivered to the spindle stock 205 immediately.

Thereafter, the first routine of the machining is performed on the newworkpiece 230 delivered to the spindle stock 205, as shown in FIG. 63. Afurther raw workpiece 230 is then also supplied to the spindle stock 203for carrying out the first routine of the machining at the same time asthe machining at the spindle stock 205. At the time that the firstroutine of the machining is performed on the workpieces 230 held by thespindle stocks 203 and 205, respectively the workpiece 230 at thespindle stock 205, after the first and second routines of the machining,is removed from the machine. The workpiece 230 at the spindle stock 203is then delivered to the spindle stock 205.

Since the machining time of the spindle stocks 203 and 205 is equal inthis way, it is not necessary for one spindle stock, having finished amachining first, to wait for the end of the machining of the otherspindle stock. The overall machining can thus be performed efficiently.

In the above-described embodiment, it was mentioned that the successivefirst and second machining routines is performed on one kind of theworkpiece 230. As will be described later, the successive machining ofthe first and second routines can also be performed on two kinds ofworkpieces 230D and 230E. That is, as shown in FIG. 64, the workpiece230D is supplied to the spindle stock 203 to have a first routine of themachining preformed thereon. Thereafter, the workpiece 230D, after thefirst routine of the machining, is delivered to the spindle stock 205from the spindle stock 203 as shown in FIG. 65, to have a second routineof the machining performed thereon.

On the other hand, the workpiece 230E, being different in kind from theworkpiece 230D, is supplied to the spindle stock 203 as shown in FIG. 65to have the first routine of the machining performed thereon. The timeit takes for the second routine of the machining of the workpiece 230Dis set to be almost equal to that for the first routine of the machiningof the workpiece 230E. Therefore, the machining end time of both theseworkpieces 230D and 230E very nearly corresponds. The workpiece 230E,after its first routine of the machining, can be immediately deliveredto the spindle stock 205 from the spindle stock 203 after the machinedworkpiece 230D is removed from the spindle stock 205, as shown in FIG.66. Thereafter, the second routine of the machining is performed on theworkpiece 230E. A new workpiece 230D is supplied to the spindle stock203 for the first routine of the machining on the workpiece 230D.

In the above-described embodiment, it was mentioned that two kinds ofworkpieces 230D and 230E can be delivered between the spindle stocks 203and 205, and that the first and second routines of the machining areperformed on the workpieces 230D and 230E. However, the first and secondroutines of the machining can be performed on two kinds of workpieces230F and 230G without delivering the workpieces between the spindlestocks 203 and 205, as will be described. That is, a first routine ofthe machining is performed on the workpiece 230F, which is supplied tothe spindle stock 203 as shown in FIG. 67, and the first routine of themachining is performed on the workpiece 230G, which is supplied to thespindle stock 205.

Next, after the holding relation between the spindle stocks 203 and 205and their respective workpieces 230F and 230G is released, eachworkpiece 230F and 230G is turned around. Thus the workpieces arereinstalled in their respective spindle stocks 203 and 205, as shown inFIG. 68. Thereafter the second routine of the machining is performed onthe workpieces 230F and 230G. At this time, a partition 246 is placedbetween the spindle stocks 203 and 205, as shown in FIG. 69 and FIG. 70.When the machining is performed toward the workpiece 230F of the spindlestock 203 and the workpiece 230G of the spindle stock 205, the chips ofthe workpieces 230F and 230G do not mix with each other, and the chipprocessing, etc., can be smoothly performed. This method is especiallyeffective where workpieces 230F and 230G are of different materials.

In the above-described embodiment, it was mentioned that the workpieceholding movement is performed by the tool rests 206A and 206B, whichhave installed a rotation tool on one installation portion 217a that canrotate and drive, as shown in FIG. 30. However, the tool rests, havingthe workpiece center rest apparatus 220A and 220B, are not criticalstructures. Any constitution is available if the tool rest has astructure for rotating and driving the tool, such as the tool rotationdriving structure 232 as shown in FIG. 29. For example, it would benatural to have the workpiece center rest apparatus 220A and 220Binstalled in the optional position, wherein which the rotation tool canbe performed, regarding the tool rest to be free to rotate and drive theplural rotation tools installed, and the tool is selectively connectedwith the spindle driving structure for tool rotation, such as the motor211 through a clutch plate, and the like.

Another embodiment of a complex machine tool will be described in FIG.71 through FIG. 90.

A complex machining machine tool 401 has a main body 402 on which aguide face 402a is disposed on the upper portion thereof, as shown inFIG. 71. On the guide surface 402a, two spindle stocks 403 and 405 faceeach other and are independently movable in a shaft axis direction ofeach spindle (not shown) of the spindle stocks 403 and 405, that is, inthe directions as shown by arrows WA and WB (Z axis direction). Twochucks 403b and 405b, which are installed in the spindles (not shown),are rotatably disposed in the direction as shown by arrows WC and WD atthe spindle stocks 403 and 405. A long sized workpiece 417 is rotatablyinstalled in the directions as shown by the arrows WC and WD between thechucks 403b and 405b such that both the right and left end portions ofthe workpiece 417 are held by the chucks 403b and 405b. Furthermore, twonuts 403c and 405c project inside the main body 402 through the guidesurface 402a at the lower side portion of the spindle stocks 403 and 405in FIG. 71, and are movably disposed, together with the spindle stocks403 and 405, in the directions as shown by the arrows WA and WB (Z axisdirection) in the main body 402. Two female screws (not shown) aredisposed at the nuts 403c and 405c in the Z axis direction.

A spindle stock driving unit 406 is provided at the main body 402, asshown in FIG. 71. The spindle stock driving unit 406 is composed ofdriving motors 407 and 409, driving screws 410 and 411, a clutch 412,and the like. That is, the driving motors 407 and 409 are disposed atboth the right and left ends of the machine body 402 in FIG. 71. Thedriving screws 410 and 411, having the same pitch, are rotatablyconnected to be rotatable in the directions as shown by arrows WE and WFwith the driving motors 407 and 409, respectively. The nuts 403c and405, as described before, are fitted in the driving screws 410 and 411.The driving screws 410 and 411 are then rotated in the directions asshown by the arrows WE and WF by engaging the driving motors 407 and 409so that the spindle stocks 403 and 405 are moved and driven in thedirection as shown by the arrow WA or in the direction as shown by thearrow WB (Z axis direction) through each nut 403c and 405c.

Two gears 410a and 411a are fixed to the ends of the driving screws 410and 411, respectively, the clutch 412 is provided between the drivingscrews 410 and 411 to be able to connect with the driving screws 410 and411. The clutch 412 has a shaft 412a, which is provided to be rotatablein the directions as shown by the arrows WE and WF and movable in thedirections as shown by the arrows WA and WB (Z axis direction). Twogears, 412b and 412c, are fixed to the respective right and left ends ofthe shaft 412a in FIG. 71.

Furthermore, two turret type tool rests 413 and 415 are provided, beingfree to move and drive only in the directions as shown by arrows WG andWH (that is, the X axis direction) on the machine body 402, as shown inFIG. 72. The directions shown by the arrows WG and WH are perpendicularto the directions shown by the arrows WA and WB. Two turret heads 413aand 415a are supported to be free to rotate and drive on the tool rests413 and 415 in the directions shown by arrows WI and WJ. A plurality oftools 416, comprising a turning tool such as a bit, a rotation tool suchas a drill, and a milling cutter, are installed on the turret heads 413aand 415a, the tools being attachable and detachable.

With the above-described structure of the complex machining machine tool401, if a long sized workpiece 417 is required to be machined, as shownin FIG. 71, both the right and left ends of the workpiece 417 are heldby the chucks 405b and 403b, respectively. When the workpiece 417 issupported between the chucks 403b and 405b, the turret heads 413a and415a of the tool rests 413 and 415 are properly rotated in the directionas shown by the arrow WI or in the direction as shown by the arrow WJ toposition a tool 416 to be used for the machining at a position facingthe workpiece 417. Next, the chucks 403b and 405b are synchronouslyrotated and driven together with the workpiece 417 in the direction asshown by the arrow WC or in the direction as shown by the arrow WD.Furthermore, the clutch 412, as shown in FIG. 71, is moved apredetermined distance to the left in the figure from the position asshown by full lines in the figure. Then the gears 412b and 412c of theclutch 412 mesh with the gears 410a and 411a fixed to each end portionof each of the driving screws 410 and 411. The driving screws 410 and411 are then connected to each other through the gears 410a and 411a andthe clutch 412.

Thereafter, the other driving motor 407 is driven, whereby either of thetwo driving motors 407 and 409 as shown in FIG. 71, for example thedriving motor 409, stops driving. The driving screw 410 is thus rotatedtogether with the gear 410a in the direction as shown by the arrow WE orin the direction as shown by the arrow WF by means of the driving motor407. When the gear 410a is rotated in the direction as shown by thearrow WE or in the direction as shown by the arrow WF, the clutch 412 isalso rotated in the direction as shown by the arrow WF or in thedirection as shown by the arrow WE due to the gear 412b being meshedwith the gear 410a. Then the driving screw 411 is rotated due to thegear 411a being meshed with the gear 412c of the clutch 412 in thedirection as shown by the arrow WE or in the direction as shown by thearrow WE in FIG. 71. Since the number of teeth of the gear 410a and thegear 411a and the number of teeth of the gear 412b and the gear 412c areall the same, the driving screws 410 and 411 are rotated in the samedirection at the same angular velocity. For this reason, the spindlestocks 403 and 405 are properly synchronously moved by the nuts 403c and405c fitted in each of the driving screws 410 and 411 in the directionas shown by the arrow WA or in the direction as shown by the arrow WB (Zaxis direction).

A predetermined machining is thus performed on the workpiece 417 suchthat the spindle stocks 403 and 405, as shown in FIG. 71, are properlysynchronously moved in the directions as shown by the arrows WA and WB(Z axis direction), and the tool rests 413 and 415 as shown in FIG. 72,are properly moved and driven together with the tool 416 in thedirections as shown by the arrows WG and WH (X axis direction).

In the above-described embodiment, it was mentioned that two mutuallyfacing spindle stocks 403 and 405 are synchronously moved in thedirections as shown by the arrows WA and WB (that is, the Z axisdirection) by means of the spindle stock driving unit 406 as shown inFIG. 71. But in the spindle stock driving unit 406, any structure issuitable if the spindle stocks 403 and 405 can be synchronously moved inthe Z axis direction. Another situation when the spindle stocks 403 and405 are synchronously moved and driven in the Z axis direction by meansof the spindle stock driving unit 406 is shown in FIG. 73 and will bedescribed hereinafter. The portions similar to the portions described inFIG. 71 and FIG. 72 are marked with the same reference numerals, andthere explanation is not repeated.

Rotary encoders 421 and 425 re installed on the end portions of thedriving screws 410 and 411 of the spindle stock driving unit 406 of thecomplex machining machine tool 401 shown in FIG. 73. The rotary encoders421 and 425 have discs 421a and 425a provided a number of magnetic andoptical marks (not shown). Sensors 421b and 425b for reading the marksare disposed at a lower position of the discs 421a and 425a in FIG. 73,respectively. A rotation angular velocity detecting portion 422 connectswith the rotary encoder 421. A driving motor control portion 423connects with the rotation angular velocity detecting portion 422. Thedriving motor control portion 423 connects with the driving motor 409. Arotation angular velocity detecting portion 426 similarly connects withthe rotary encoder 425 installed on the end portion of the driving screw411. The rotation angular velocity detecting portion 426 also connectswith the driving motor control portion 423.

If a long sized workpiece 417 is required to be machined with thecomplex machining machine tool 401 is shown in FIG. 73, both the rightand left end portions of the workpiece 417 in the figure are held by thechucks 403b and 405b installed in the spindle stocks 403 and 405. Theturret heads 413a and 415a of the tool rests 413 and 415, as shown inFIG. 72, are properly rotated in the direction as shown by the arrow WIor in the direction as shown by the arrow WJ. Then the tools 416 to beused for the machining are positioned facing the workpiece 417. In thisstate, the chucks 403b and 405b are simultaneously rotated together withthe workpiece 417 in the direction as shown by the arrow WC or in thedirection as shown by the arrow WD. The driving motor 407 as shown inFIG. 73 is driven to rotate the driving screw 410 in the direction asshown by the arrow WE or in the direction as shown by the arrow WF. Thenthe spindle stock 403 is moved together with the chuck 403b by the nut403c in the direction as shown by the arrow WA or WB (that is, Z axisdirection). At the same time, the disc 421a of the rotary encoder 421 isalso rotated together with the driving screw 410 in the direction asshown by the arrow WE or WF. The sensor 421b then reads the marks on thedisc 421a and outputs to the rotation angular velocity detecting portion422.

The rotation angular velocity detecting portion 422, on the basis of thereading, detects the rotation angular velocity of the driving screw 410in the direction as shown by the arrow WE or in the direction as shownby the arrow WF, and outputs a control signal corresponding to therotation angular velocity to the driving motor control portion 423. Thedriving motor control portion 423, on the basis of the outputted signal,then controls the driving motor 409. Thus the driving screw 411 isrotated in the same direction as the screw 410 and equals the rotationangular velocity of the driving screw 410. Therefore the spindle stock405 is moved by the nut 405c together with the chuck 405b in thedirection as shown by the arrow WA or in the direction as shown by thearrow WB (Z axis direction) synchronized with the spindle stock 403.

The disc 425a of the rotary encoder 425 as shown in FIG. 73 is alsorotated together with the driving screw 411 in the direction as shown bythe arrow WE or in the direction as shown by the arrow WF. The sensor425b reads the marks on the disc 425a and outputs them to the rotationangular velocity detecting portion 426. The rotation angular velocitydetecting portion 426, on the basis of the reading, detects the rotationangular velocity of the driving screw 411 in the directions as shown bythe arrows WE or WF, and outputs the rotation angular velocity to thedriving screw 411 in the directions as shown by the arrows WE or WF, andoutputs the rotation angular velocity to the driving motor controlportion 423. Then the driving motor control portion 423 outputs acorrected driving signal to the driving motor 409 such that the rotationangular velocity is compared with the rotation angular velocity of thedriving motor 407 outputted from the rotation angular velocity detectingportion 422. The driving motor 409 on the basis of the corrected drivingsignal, rotates the driving screw 411 in the direction as shown by thearrow WE or in the direction as shown by the arrow WF. Accordingly, therotation angular velocity of the driving screws 410 and 411 stays thesame. The spindle stocks 403 and 405 are thus simultaneously andsmoothly moved in the directions as shown in the arrows WA and WB (Zaxis direction), supporting the workpiece 416 between the chucks 403band 405b.

In this way the spindle stocks 403 and 405 as shown in FIG. 73 aresimultaneously moved together with the workpiece 417 in the directionsas shown by the arrows WA and WB (the Z axis direction). Furthermore,the tool rests 413 and 415 are properly moved together with the tool 416in the directions as shown by the arrows WG and WH (the X axisdirection). Then the workpiece 417 is machined into a predeterminedshape by means of each tool 416.

Now will be described the situation where a bar shaped workpiece ismachined by mean of the complex machining machine tool 401. If a barshaped workpiece 420 as shown in FIG. 74 is required to be machined, thebar shaped workpiece 420 is pushed out through the chuck 403b installedon the spindle stock 403 in the direction as shown by the arrow WB bymeans of the barfeeder apparatus (not shown). Thus the end of the barshaped workpiece 420 on which the first routine is to be performed isset to project from the chuck 403b in the direction as shown by thearrow WB. Thereafter, the turret head 413a of the tool rest 413 isproperly rotated in the direction as shown by the arrow WI or in thedirection as shown by the arrow WJ in FIG. 74. Then the tool 416 forturning the outside diameter is positioned at a position facing the barshaped workpiece 420. Next, the chuck 403b is rotated together with thebar shaped workpiece 420 in the direction a shown by the arrow WC. Whenthe bar shaped workpiece 420 is rotated in the direction as shown by thearrow WC, the driving motor 407 as shown in FIG. 71 is driven, and thedriving screw 410 is properly rotated in the direction as shown by thearrow WE or in the direction as shown by the arrow WF. Moreover, thespindle stock 403 is properly moved by the nut 403c in the direction asshown by the arrow WA or in the direction as shown by the arrow WA or inthe direction as shown by the arrow WB (the Z axis direction). At thesame time, the tool rest 413 as shown in FIG. 74 is moved and driventogether with the tool 416 in the directions as shown by the arrows WGand WH (the X axis direction). Thus the machining for turning isperformed on the outside cylindrical portion of the bar shaped workpiece420 by means of the tool 416.

When the turning performed on the outside cylindrical portion of the barshaped workpiece 420 is completed, the tool rest 413 is properly movedin the direction as shown by the arrow WG to retract from the bar shapedworkpiece 420. The turret head 413a of the tool rest 413 is properlyrotated in the direction as shown by the arrow WI or in the direction asshown by the arrow WJ. Then the tool 416 for turning the insidediameter, such as a drill or a boring tool, is positioned at a positionfacing the bar shaped workpiece 420. Thereafter, the tool rest 413 isfed a predetermined distance together with the tool 416 in the directionas shown by the arrow WH in FIG. 75. The spindle stock 403 is moved anddriven properly in the directions as shown by the arrows WA and WB (Zaxis direction) with the bar shaped workpiece 420 held by the chuck403b. In this way, the inside diameter portion of the bar shapedworkpiece 420 is machined by means of the tool 416.

When the inside diameter portion of the bar shaped workpiece 420 hasbeen machined as shown in FIG. 75, the spindle stock 403 is properlymoved in the direction as shown by the arrow WA to be away from the toolused for the machining of the inside diameter portion. The tool rest 413is moved in the direction as shown by the arrow WG to retract from thebar shaped workpiece 420. When the tool rest 413 is retracted, theturret head 413a is properly rotated in the directions as shown by thearrows WI or WJ. Then a tool 416, such as an end mill, is positioned ata position facing the bar shaped workpiece 420. Thereafter, the rotationof the chuck 403b in the direction as shown by the arrow WC is stopped,and the tool 416 is rotated and driven. In this state the tool rest 413is fed a predetermined distance in the direction as shown by the arrowWH in FIG. 76, and the spindle stock 403 is moved and driven in thedirections as shown by the arrows WA and WB (the Z axis direction). Inthis way the milling machining is performed on the bar shaped workpiece420. The chuck 403b of the spindle stock 403 is properly rotated in thedirections as shown by the arrows WC and WD by C-axis control. In thisstate, the milling machining can be performed. After the millingmachining, the tool rest 413 is retracted from the bar shaped workpiece420 in the direction as shown by the arrow WG. A cutting-off tool 416 isthen positioned at a position facing the bar shaped workpiece 420.

When the first routine of the machining is performed on the top endportion of the bar shaped workpiece 420 is completed, the tool rest 413is moved in the direction as shown by the arrow WG to be retracted fromthe bar shaped workpiece 420, and the rotation of the chuck 403b in thedirections as shown by the arrows WC and WD is stopped. Thereafter, thechuck 403b is loosened. The barfeeder apparatus (not shown) is driven,and the bar shaped workpiece 420 is pushed out a predetermined length inthe direction as shown by the arrow WB, through the chuck 403b. When thebar shaped workpiece 420 is pushed out the predetermined length from thechuck 403b, the chuck 403b is fastened to hold the bar shaped workpiece420. Then the portion to which the first routine of the machining wasperformed on the bar shaped workpiece 420 is fitted into the chuck 405bwith the chuck 405b of the spindle stock 405 loosened, and the tool rest405 is moved in the direction as shown by the arrow WA in FIG. 76. Thechuck 405b is then fastened, and the bar shaped workpiece 420 issupported between the chucks 403b and 405b.

A cutting-off tool 416 installed on the tool rest 413 is then positionedat a position facing the bar shaped workpiece 420. When the tool 416faces the bar shaped workpiece 420, the portion (called part 420ahereinafter) on which the first routine of the machining of the barshaped workpiece 420 had finished and the raw portion to which will beperformed the second routine of the machining of the bar shapedworkpiece 420 is cut off from the other raw portion of the bar shapedworkpiece 420 by means of the tool 416. The chucks 403b and 405b, asshown in FIG. 77, are synchronously rotated together with the bar shapedworkpiece 420 in the direction as shown by the arrow WC by means of themethod described earlier, and the tool rest 413 is fed a predetermineddistance in the direction as shown by the arrow WH.

When the part 420a is cut off as shown in FIG. 77, the tool rest 413 isretracted from the bar shaped workpiece 420 in the direction as shown bythe arrow WG, and the spindle stock 405 is moved a predetermineddistance in the direction as shown by the arrow WB, that is, in thedirection away from the spindle stock 403, with the part 420a held bythe chuck 405b. Thereafter, the rotation of the chuck 403b in thedirection as shown by the arrow WC is stopped, and the chuck 403b isloosened. Next, the bar shaped workpiece 420 is pushed out from thechuck 403b in the direction as shown by the arrow WB as shown in FIG.78. The raw portion of the bar shaped workpiece 420 is projected apredetermined length from the chuck 403b in the direction as shown bythe arrow WB. In this state, the chuck 403b is fastened, and the barshaped workpiece 420 is held.

Thereafter, the first routine is performed on the raw portion cf the barshaped workpiece 420. At the same time, the second routine is performedon the part 420a. At first the turret heads 413a and 415a cf the toolrests 403 and 405 are properly rotated in the direction as shown by thearrow WI or in the direction as shown by the WJ in FIG. 78, and thetools 416 for turning the outside diameter are positioned at a positionfacing the bar shaped workpiece 420 and the part 420a. Thereafter, eachchuck 403b and 405b of the tool rests 403 and 405 is rotated in thedirection as shown by the arrow WC. The turning machining is performedin a predetermined manner on each outside cylindrical portion of the barshaped workpiece 420 and the part 420a by means of the tools 416. Thespindle stocks 403 and 405 are properly and independently moved anddriven in the directions as shown by the arrows WA and WB (Z axisdirection), and the tool rests 413 and 415 are properly moved togetherwith the tools 416 in the directions as shown by the arrows WG and WH,that is, in the X axis direction.

When each outside cylindrical portion of the bar shaped workpiece 420and the part 420a has been turned as shown in FIG. 78, the tool rests413 and 415 are retracted from the bar shaped workpiece 420 and the part420a, and tool 416 installed on the tool rests 413 and 415 for turningthe inner diameter are respectively positioned facing the bar shapedworkpiece 420 and the part 420a. Thereafter, the tool rests 413 and 415are fed a predetermined distance in the direction as shown by the arrowWH in FIG. 79. The tools 416, as described before, face the right endsurface of the bar shaped workpiece 420 and the left end surface of thepart 420a, respectively. The spindle stocks 403 405 are thenindependently moved in the directions as shown by the arrows WA and WB(the Z axis direction), respectively. In this way, each inside diameterportion of the bar shaped workpiece 420 and the part 420ais machined ina predetermined manner.

After each inside diameter portion of the bar shaped workpiece 420 andthe part 420ais machined in the predetermined shape as shown in FIG. 79,the spindle stock 403 is moved in the direction as shown by the arrowWA. and the spindle stock 405 is moved in the direction as shown by thearrow WB, to remove each tool 416 from each inside diameter portion. Thetool rests 413 and 415 are then moved in the direction as shown by thearrow WG to retract from the bar shaped workpiece 420 and the part 420a.Furthermore, the rotation of the chucks 403b and 405b in the directionas shown by the arrow WC is stopped.

Then a milling machining is performed on the bar shaped workpiece 420 bymeans of the tool 416. The tool rest 413, as shown in FIG. 80, is fed apredetermined distance, together with the tool 416 for milling, in thedirection as shown by the arrow WH. The spindle stock 403 is movedtogether with the bar shaped workpiece 420 in the directions as shown bythe arrows WA and -;B (the Z axis direction). The chuck 403b is thenproperly rotated in the directions as shown by the arrows WC and WD bymeans of the C-axis control so that the milling machining can beperformed. The second routine is performed in parallel with the millingmachining. The other tool rest 415 is fed a predetermined distancetogether with the tool 416, such as a drill, in the direction as shownby the arrow WH, to have the tool 416 face the machining portion of thepart 420a, as shown in FIG. 80. The spindle stock 405 is moved togetherwith the part 420a in the directions as shown by the arrows WA and WB (Zaxis direction) to perform a drill machining and the like on the part420a by means of the tool 416. When the second routine is finished withrespect to the parts 420a, the chuck 405b is loosened to detach themachined part 420a from the chuck 405b, and part 420a is thrown into aparts catcher 419, as seen at the bottom of FIG. 81. The first routineis thus performed in parallel with the second routine, so thatsuccessive machining is performed on the bar shaped workpiece 420, and alarge number of the machined parts 420a are made.

In the above-described embodiment, it was mentioned that the bar shapedworkpiece 420 was fed a predetermined length through the chuck 403b fromthe spindle stock 403 in the direction as shown by the arrow WB at twotimes, that is, one time before the cutting-off and the other time afterthe cutting-off, by means of the barfeeder apparatus (not shown). Butthe time that the bar shaped workpiece 420 is fed is not critical. Thedelivering activity can finish at one time, either before thecutting-off or after the cutting-off.

In the above-described embodiment, it was also mentioned that after thefirst routine finishes on the bar shaped workpiece 420, the portion onwhich the first routine was performed is fed in the direction shown bythe arrow WB by means of the barfeeder apparatus, is held by the chuck405b, and is cut off to leave the part 420a separate from the remainingraw portion. However, it may be that the bar shaped workpiece 420 ispulled out the quantity to have the first routine performed thereon nextfrom the chuck 403b in the direction as shown by the arrow WB by meansof the spindle stock 405, without the barfeeder apparatus and before thecutting-off, and is then cut off. That is, after the first routinefinishes on the bar shaped workpiece 420, as shown in FIG. 76, therotation of the chuck 403b in the direction as shown by the arrow WC isstopped. The chuck 405b of the spindle stock 405 is then loosened.Furthermore, the tool rest 405 is moved a predetermined distance in thedirection as shown by the arrow WA, and the portion of the bar shapedworkpiece 420 to which the first routine had been performed is fittedinto the chuck 405b. At the time that this portion is fitted into thechuck 405b, the chuck 405 b is fastened, and the bar shaped workpiece420 is held. At the same time, the chuck 403b is loosened, and theholding relation between the chuck 403b and the bar shaped workpiece 420is released. In this state the spindle stock 405 is moved apredetermined distance together with the chuck 405b in the direction asshown by the arrow WB, that is, in the direction away from the spindlestock 403. The bar shaped workpiece 420 is thus pulled out, with aquantity thereof to which will next be performed the first routine, fromthe chuck 403b in the direction as shown by the arrow WB, being pulledby the spindle stock 405. When the bar shaped workpiece 420 is pulledout the quantity which will next have the first routine performedthereon from the chuck 403b, the chuck 403b is fastened to hold the barshaped workpiece 420.

In this way, when the bar shaped workpiece 420 is supported between thechucks 403b and 405b, the chucks 403b and 405b are synchronously rotatedin the direction as shown by the arrow WC, and the spindle stocks 403and 405 are properly moved together with the bar shaped workpiece 420 inthe directions as shown by the arrows WA and WB (the Z axis direction).The tool 416 for cutting-off, which is installed in the tool rest 413,is positioned to face the portion of the bar shaped workpiece 420 to becut off. The tool rest 413 is then fed a predetermined distance in thedirection as shown by the arrow WH to cut the bar shaped workpiece 420by means of the tool 416. In this way the part 420a is cut off from theremaining raw portion of the bar shaped workpiece 420. The bar shapedworkpiece 420 is then pulled out a length corresponding to the length ofworkpiece needed to have performed a next first routine of the machiningto be able to start the machining immediately.

If a long and slender shaft shaped workpiece 429 as shown in FIG. 82 ismachined making use of the complex machining machine tool 401, the shaftshaped workpiece 429 is held by the chuck 403b to project apredetermined length from the chuck 403b installed in the spindle stock403 in the direction as shown by the arrow WB. When the shaft shapedworkpiece 429 is held by the chuck 403b as shown in FIG. 82, the chuck403b is rotated in the direction as shown by the arrow WC. At the sametime, the tool 416 for turning is positioned at a position facing theshaft shaped workpiece 429 by the turret head 413a of the tool rest 413by being properly rotated in the direction as shown by the arrow WI orin the direction as shown by the arrow WJ in FIG. 82. The spindle stock403 is then moved and driven together with the chuck 403b in thedirections as shown by the arrows WA and WB (the Z axis direction).Moreover, the tool rest 413 is properly moved and driven in thedirections as shown by the arrow WG and WH (the X axis direction). Thusturning is performed on the portion of the shaft shaped workpiece 429projecting from the chuck 403b in the direction as shown by the arrow WBby means of the tool 416.

When the turning has been performed on the projecting portion of theshaft shaped workpiece 429, the tool rest 413 is properly moved in thedirection as shown by the arrow WG to retract from the shaft shapedworkpiece 429. Thereafter, a workpiece holding portion 405d of the chuck405b, which is installed in the spindle stock 405 as shown in FIG. 82,is loosened. The spindle stock 405 is then moved a predetermineddistance together with the chuck 405b toward the spindle stock 403 inthe direction as shown by the arrow WA, and the machined portion of theshaft shaped workpiece 429 is fitted into the workpiece holding portion405d. At the time the portion is fitted into the workpiece holdingportion 405d, the workpiece holding portion 405d is fastened and theshaft shaped workpiece 429 is held. At the same time, a workpieceholding portion 403d of the chuck 403b is loosened, and the holdingrelation between the chuck 403b and the shaft shaped workpiece 429 isreleased.

The spindle stock 405 is then moved a predetermined distance togetherwith the chuck 405b in the direction as shown by the arrow WB, that is,in the direction away from the spindle stock 403. Then the shaft shapedworkpiece 429 is pulled out a predetermined length from the chuck 403bin the direction as shown by the arrow WB, being pulled by the spindlestock 405, as shown in FIG. 83. Then when the raw portion of the shaftshaped workpiece 429 is pulled out the predetermined length from thechuck 403b, the workpiece holding portion 403d of the chuck 403b isfastened to hold the shaft shaped workpiece 429.

The chucks 403b and 405b, as shown in FIG. 83, are then synchronouslyrotated in the direction as shown by the arrow WC and at the same timethe tool 416 used for machining is positioned to face the shaft shapedworkpiece 429 by the turret head 415a of the tool rest 415 beingproperly rotated in the direction as shown by the arrow WI or in thedirection as shown by the arrow WJ. Thereafter, turning is performed onthe raw portion (the raw portion of the nearby chuck 403b is excluded)of the shaft shaped workpiece 429, which is pulled from the chuck 403bin the direction as shown by the arrow WB, in such a manner that thespindle stocks 403 and 405 are synchronously and properly moved in thedirections as shown by the arrows WA and WB (the Z axis direction), andthe tool rest 415 is moved together with the tool 415 in the directionsas shown by the arrows WG and WH (the X axis direction).

When the turning is completed on the raw portion, the tool rest 415 isproperly moved in the direction as shown by the arrow WG as shown inFIG. 84 to be retracted from the shaft shaped workpiece 429. Next, thetool 416 used for the machining is positioned at a position facing theshaft workpiece 429 by the tool rest 413 being properly rotated in thedirection as shown by the arrow WI or in the direction as shown by thearrow WJ. Then the spindle stocks 403 and 405 are synchronously andproperly moved in the directions as shown by the arrows WA and WB (the Zaxis direction). The tool rest 413 is also then properly moved togetherwith the tool 416 in the directions as shown by the arrows WG and WH(the X axis direction). The turning has then been performed on the rawportion of the shaft shaped workpiece 429 adjacent to the chuck 403b.

When the turning has been performed on the outside cylindrical portionof the shaft shaped workpiece 429 as shown in FIG. 84, the rotation ofthe chucks 403b and 405b in the direction as shown by the arrow WC isstopped, and the tool rest 413 is retracted from the shaft shapedworkpiece 429. Thereafter, the tool 416 for milling is positioned facingthe shaft shaped workpiece 429, as shown in FIG. 85, by the tool rest415 being properly rotated in the direction as shown by the arrow WI orin the direction as shown by the arrow WJ. The tool rest 415 is then feda predetermined distance together with the tool 416 for milling in thedirection as shown by the arrow WH. Furthermore, the spindle stocks 403and 405 are synchronously and properly moved in the directions as shownby the arrows WA and WB (the Z axis direction). The milling machining isthus performed on the outside surrounding portion of the shaft shapedworkpiece 429. The milling machining can be performed in such a mannerthat the chucks 403b and 405b are synchronously and properly rotated inthe directions as shown by the arrows WC and WD by means of the C-axiscontrol. After the milling machining finishes, the tool rest 415 isretracted from the shaft shaped workpiece 429.

When the end portion of the shaft shaped workpiece 429 is machined at apredetermined length, the holding relation between the chuck 405b andthe shaft shaped workpiece 429 is released by loosening the chuck 405b.Moreover, the spindle stock 405 is moved a predetermined distance in thedirection as shown by the arrow WA. Then the chuck 405b is moved in thedirection as shown by the arrow WA, making the machined portion of theshaft shaped workpiece 429 successively pass into the workpiece holdingportion 405d, to be positioned at a position adjacent to the chuck 403b.The chuck 405b is then fastened to hold the shaft shaped workpiece 429,and the chuck 403b is loosened. Next, the spindle stock 405 is moved apredetermined distance together with the chuck 405b in the direction asshown by the arrow WB, to pull out the shaft shaped workpiece 429 fromthe chuck 403b a predetermined length. When the shaft shaped workpiece429 is pulled out the predetermined length from the chuck 403b, thechuck 403b is fastened to hold the shaft shaped workpiece 429. Thechucks 403b and 405b are then synchronously rotated in the direction asshown by the arrow WC. Furthermore, the spindle stocks 403 and 405 aremoved together with the shaft shaped workpiece 429 in the directions asshown by the arrows WA and WB. A portion of the shaft shaped workpiece429 to be cut is then positioned to face a tool for cutting-off 416installed in the tool rest 413. Thereafter, the tool rest 413 is fed apredetermined distance together with the tool 416 for cutting-off in thedirection as shown by the arrow WH as shown in FIG. 86. Then the shaftshaped workpiece 429 is cut by means of the tool 416 in the directionsas shown by the arrows WG and WH, and the machined portion (called part429a, hereinafter) is cut off from the other raw portion of the shaftshaped workpiece 429.

When the shaft shaped workpiece 429 is cut, the tool rest 413 isretracted from the shaft shaped workpiece 429, and the spindle stock 405is moved a predetermined distance, together with the chuck 405b, in thedirection as shown by the arrow WB as shown in FIG. 87. The part 429a ismoved the predetermined distance together with the chuck 405b in thedirection shown by the arrow WB. The spindle stock 405 is then moved anddriven in the directions as shown by the arrows WA and WB (the Z axisdirection), and the tool rest 415 is moved and driven together with thetool 416 in the directions as shown by the arrows WG and WH (the X axisdirection) to perform a predetermined machining on the part 429a. Inparallel with this, the spindle stock 403 is moved and driven in thedirections as shown by the arrows WA and WB (the Z axis direction).Moreover, the tool rest 413 is moved and driven together with the tool416 in the directions as shown by the arrows WG and WH (the X axisdirection). Then the same machining as shown in FIG. 82 is performed onthe raw portion cf the shaft shaped workpiece 429 held by the chuck403b. When the machining finishes on the part 429a, the chuck 405b isloosened to remove the part 429a from the chuck 405b, and the part 429ais thrown in the parts catcher 419, as shown in FIG. 88.

A situation where a long sized workpiece 427, as shown in FIG. 89, isfed from the spindle stock 403 in the direction as shown by the arrow WBwithout using the barfeeder apparatus and machining on the workpiece 427is performed without using a center rest will be described. That is, inorder to machine the workpiece 427, the workpiece 427 is set so as toproject a predetermined length from the chuck 403b through the workpieceholding portion 403d of the chuck 403b installed on the spindle stock403 in the direction as shown by the arrow WB. Thereafter, the chuck403b is rotated together with the workpiece 427 in the direction asshown by the arrow WC, and the tool 416 used for machining, among thetools 416 installed on the tool rest 413, is positioned to face theworkpiece 427. Next, the spindle stock 403 is moved together with thechuck 403b (that is, the workpiece 427) in the direction as shown by thearrows WA and WB (the Z axis direction), and the tool rest 413 is movedtogether with the tool 416 for machining in the direction as shown bythe arrows WG and WH (X axis direction) and the end portion of theworkpiece 427 is machined by means of the tool 416.

When the end portion of the workpiece 427 has been machined, therotation of the chuck 403b in the direction as shown by the arrow WC isstopped, and the tool rest 413 is moved in the direction as shown by thearrow WG to retract from the workpiece 427. The tool used for the nextmachining (see FIG. 90 (a) ) of the tools 416 installed in the tool rest413 is then positioned to face the workpiece 427. Next, the workpieceholding portion 405d of the chuck 405b, which is installed in thespindle stock 405, as shown in FIG. 89, is loosened. In this state thespindle stock 405 is moved a predetermined distance together with thechuck 405b toward the spindle stock 403 in the direction as shown by thearrow WA to fit the end portion of the workpiece 427 into the workpieceholding portion 405d as shown in FIG. 90(a). When the end portion fitsinto the workpiece holding portion 405d, the workpiece holding portion405d is fastened, and the end portion is held by the spindle stock 405.At the same time, the workpiece holding portion 403d of the chuck 403bis loosened a little. The holding relation between the spindle stock 403and the workpiece 427 is revised so as to move in the direction as shownby the arrows WA and WB (the Z axis direction), although the workpiece427 can't rotate in the direction as shown by the arrows WC and WD onthe chuck 403b.

When the workpiece 427 is held by each of the chucks 403b and 405b ofthe spindle stocks 403 and 405, the spindle stocks 403 and 405 aresynchronously moved in the directions as shown by the arrows WA and WB,and the chucks 403b and 405b are synchronously rotated in the directionas shown by the arrow WC or in the direction as shown by the arrow WD.The tool rest 413 is fed a predetermined quantity, together with thetool 416, for machining in the direction as shown by the arrow WH. Thenthe tool rest 413 is positioned at a position near the chuck 403b of thespindle stock 403 as shown in FIG. 90 (a), and the tool 416 formachining is positioned at a position of the start of machining.

Thereafter, with the spindle stock 403 positioned at the machiningposition, the spindle stock 405 as shown in FIG. 90 (a) is graduallymoved, together with the chuck 405b, in the direction as shown by thearrow WB, that is, in the direction away from the spindle stock 403.Then the workpiece 427 is pulled in the direction as shown by the arrowWB by the spindle stock 405, and the raw portion of the workpiece 427 isgradually pulled out from the chuck 403b in the direction as shown bythe arrow WB through the workpiece holding portion 403d of the chuck403b. Thus a successive machining is performed on the raw portion of theworkpiece 427 being gradually pulled out from the chuck 403b by means ofthe tool 416, as shown in FIG. 90 (a) and FIG. 90 (b), the tool rest 413being properly moved together with the tool 416 in the directions asshown by the arrows WG and WH. The chuck 403b of the spindle stock 403holds the workpiece 427 loosened a little so as to be able to move inthe directions as shown by the arrows WA and WB (the Z axis direction),although the workpiece 427 is not rotated in the directions as shown bythe arrows WC and WD, and the machining by the tool rest 413 isperformed ar a position near the chuck 403b. Thus the chuck 403b fillsthe role of a center rest, the workpiece 427 being machined withoutdeflecting from its center. The workpiece 427 is smoothly pulled out inthe direction as shown by the arrow WB on account of the above describedreasons.

In the above-described embodiment, it was mentioned that the spindlestock 405 was moved toward the spindle stock 403 in the direction asshown by the arrow WA, and then held by the spindle stock 405. However,the above method of holding the end portion of the workpiece 427 withthe spindle stock 405 is not critical. Any holding method is availableif the end portion can be properly held by the spindle stock 405. Forexample, the end portion of the workpiece 427 may be held by the spindlestock 405 in such a manner that the spindle stock 403 is moved apredetermined distance together with the workpiece 427 toward thespindle stock 405 in the direction as shown by the arrow WB. The endportion of the workpiece 427 can be held by the spindle stock 405 insuch a manner that the spindle stocks 403 and 405 are relatively movedin the Z axis direction, and the interval between the spindle stocks 403and 405 is narrowed.

Another example will be described in FIG. 91, that is, the spindlestocks 403 and 405 face each other and are synchronously moved in thedirections as shown by the arrows WA and WB. The same portions asdescribed in FIG. 73 are marked with the same numerals, and theexplanation of these portions will be omitted.

The spindle stock driving unit 406 is provided with the machine body 402of the complex machining machine tool 401 as shown in FIG. 91. Thespindle stock driving unit 406 has driving motors 407 and 409 drivingscrews 410 and 411, rotary encoders 421 and 425, rotation angularvelocity quantity detecting portions 422a and 422b driving motor controlportion 423a and 423b, and the like. That is, the driving motors 407 and409 are provided at both the right end portions of the machine body 402in FIG. 91. Each of the driving motor control portions 423as and 423b isconnected with its respective driving motor 407 and 409. The drivingmotor control portions 423a and 423b connect with a rotation angularvelocity quantity comparing portion 426a and a main control portion426b. The rotation angular velocity quantity comparing portion 426a alsoconnects with the main control portion 426b. A machining program memory426c connects with the main control portion 426b.

The driving screws 410 and 411, having the same pitch, rotatably connectwith the driving motors 407 and 409, and are rotatable in the directionsas shown by the arrows WE and WF. Each of the nuts 403c and 405c, asdescribed before, fits in the respective driving screws 410 and 411. Thespindle stocks 403 and 405 are moved and driven by the nuts 403c and405c in the directions as shown by the arrow WA or in the direction asshown by the arrow WA or in the direction as shown by the arrow WB (theZ axis direction), the driving motors 407 and 409 being driven to rotatethe driving screws 410 and 411 in the direction as shown by the arrow WEor in the direction as shown by the arrow WF.

The rotary encoders 421 and 425 are installed in the end portions of thedriving screws 410 and 411. The rotary encoders 421 and 425 are discs421a and 425a provided with a number of magnetic and optical marks (notshown). The sensors 421b and 425b read the marks that are provided atthe lower portion of the discs 421a and 425a in FIG. 91. The rotaryencoders 421 and 425 are connected with the respective rotation angularvelocity quantity detecting portions 422a and 422b. The rotation angularvelocity quantity detecting portions 422a and 422b connect with therotation velocity quantity comparing portion 426a.

With the above complex machining machine tool 401, if the long sizedworkpiece 417 is required to be machined, as shown in FIG. 91, both theright and left end portions of the workpiece 417 are held by the chucks403b and 405b. When the workpiece 417 is held by the chucks 403b and405b the chucks 403b and 405b are synchronously rotated and driventogether with the workpiece 417 in the direction as shown by the arrowWC or in the direction as shown by the arrow WD on the basis of amachining program used for the machining of the workpiece 417 stored inthe machining program memory 426c. At the same time, the turret heads413a and 415a of the tool rests 413 and 415, as shown in FIG. 72, areproperly rotated and driven in the direction as shown by the arrow WI orin the direction as shown by the arrow WJ. Thus the tool 416 to be usedfor the machining is positioned facing the workpiece 417. Thereafter,driving signals D1 and D2 indicating the synchronous movement of thespindle stocks 403 and 405 are outputted to each of the driving motorcontrol portions 423a and 423b from the main control portion 426b. Thedriving motor control portions 423a and 423b receive signals to rotateand drive the driving motors 407 and 409 at the same speed. Then thedriving screws 410 and 411 connected with the driving motors 407 and 409rotate at the same angular velocity in the direction as shown by thearrow WE or in the direction as shown by the arrow WF. As a result, thespindle stocks 403 and 405 are synchronously moved by the nuts 403c and405c at the same speed in the directions as shown by the arrows WA andWB (that is, in the Z axis direction). At this point the discs 421a and425a of the rotary encoders 421 and 425 are also rotated in thedirection as shown by the arrow WE or in the direction as shown by thearrow WF. The sensors 421b and 425b then read the marks on the discs421a and 425a. The read signals are sent to the rotation angularvelocity quantity detecting portions 422a and 422b.

The rotation angular velocity quantity detecting portions 422a and 422b,on the basis of the received signals, detect the rotation angularvelocity quantities of the driving screws 410 and 411 in FIG. 91 in thedirection as shown by the arrow WE or in the direction as shown by thearrow WF. Detecting signals S1 and S2, corresponding to the rotationangular velocity quantities, are outputted to the rotation angularvelocity quantity comparing portion 426a. Then the rotation angularvelocity quantity comparing portion 426a, on the basis of the signals,outputs control signals C1 and C2 to the driving control portions 423aand 423b so that the difference between the detected rotation angularvelocity quantities of the driving screws 410 and 411 becomes zero. Thedriving motor control portions 423a and 423b, on the basis of thesignals, drive and control the driving motors 407 and 409. Accordingly,the rotation angular velocity quantities of the driving screws 410 and411, in the directions as shown by the arrows WE and WF, always stay thesame by means of the above-described control, even if the rotation ofthe motors 407 and 409 changes while the spindle stocks 403 and 405 aresynchronously moving in the directions as shown by the arrows WA and WB(that is, the Z axis direction). Therefore synchronous movement issmoothly performed.

In this way the spindle stocks 403 and 405, as shown in FIG. 91, aresynchronously moved together with the workpiece 417 in the direction asshown by the arrows WA and WB (the Z axis direction). Moreover, the toolrests 413 and 415 are properly moved together with the tools 416 in thedirections as shown by the arrows WG and WH (the X axis direction). Thusthe workpiece 417 is machined in a predetermined shape by the means ofeach tool 416.

If a slender and long sized and shaft shaped workpiece 429 as shown inFIG. 92 is machined, the shaft workpiece 429 is preset to project apredetermined length from the spindle stock 403 in the direction asshown by the arrow WB through the chuck 403b installed in the spindlestock 403. When the shaft shaped workpiece 429 is set, the chuck 403b isrotated in the direction as shown by the arrow WC. At the same time, theturret head 413a of the tool rest 413 is properly rotated in thedirection as shown by the arrow WI or in the direction as shown by thearrow WJ in FIG. 92. A tool 416 for turning is then positioned facingthe shaft shaped workpiece 429. Next, in this state, the spindle stock403 is moved and driven together with the chuck 403b in the directionsas shown by the arrows WA and WB (the Z axis direction). Thus themachining for turning is performed on the outside cylindrical portion ofthe shaft shaped workpiece 429 projecting from the chuck 403b of thespindle stock 403 in the direction as shown by the arrow WB by means ofthe tool 416.

When the turning is completed on the outside cylindrical portion of theshaft shaped workpiece 429, the tool rest 413 is properly moved in thedirection as shown by the arrow WG to be retracted from the shaft shapedworkpiece 429. Furthermore, the rotation of the chuck 403b in thedirection as shown by the arrow WC is stopped. Thereafter, the workpieceholding portion 405d of the chuck 405b installed in the spindle stock405, as shown in FIG. 92, is loosened. In this state, the spindle stock405 is moved a predetermined distance, together with the chuck 405b,toward the spindle stock 403, in the direction as shown by the arrow, WAas shown in FIG. 93, to insert the machined portion of the shaft shapedworkpiece 429 into the workpiece holding portion 405d. When the machinedportion is inserted into the workpiece holding portion 405d, theworkpiece holding portion 405d is fastened to hold the shaft shapedworkpiece 429 by the spindle stock 405. At the same time, the workpieceholding portion 403d of the chuck 403d is loosened to release theholding relation between the spindle stock 403 and the shaft shapedworkpiece 429.

The spindle stock 405 is then moved a predetermined distance togetherwith the chuck 405b in the direction as shown by the arrow WB in FIG.93, that is, in the direction away from the spindle stock 403. Then theshaft shaped workpiece 429 is pulled by the spindle stock 405, as shownin FIG. 94, and its raw portion is pulled out a predetermined lengththrough the chuck 403b of the spindle stock 403 in the direction asshown by the arrow WB. After the raw portion of the shaft shapedworkpiece 429 is pulled out the predetermined length from the spindlestock 403, the workpiece holding portion 403d of the chuck 403b isfastened to hold the shaft shaped workpiece 429 with the spindle stocks403 and 405.

In this state the chucks 403b and 405b, as shown in FIG. 94, aresynchronously rotated in the direction as shown by the arrow WC. Thetool 416 for turning, to be used in the machining, is positioned facingthe shaft shaped workpiece 429 by the turret head 415a of the tool rest415 being properly rotated in the direction as shown by the arrow WI orin the direction as shown by the arrow WJ. Thereafter the spindle stocks403 and 405 are synchronously and properly moved in the directions asshown by the arrows WA and WB (the Z axis direction), and tool rest 415is moved together with the tool 416 for turning in the directions asshown by the arrows WG and WH (the X axis direction). Thus the turningis performed on the raw portion of the shaft shaped workpiece 429 whichhas been pulled out anew.

When the turning is completed on the raw portion of the shaft shapedworkpiece 429, as shown in FIG. 94, the rotation of the chucks 403b and405b in the direction as shown by the arrow WC is stopped, and the toolrest 415 is moved in the direction as shown by the arrow WG to beretracted from the shaft shaped workpiece 429. Thereafter the workpieceholding portion 405d of the chuck 405b is loosened to release theholding relation between the spindle stock 405 and the shaft shapedworkpiece 429. The spindle stock 405 is then moved a predetermineddistance toward the spindle stock 403 in the direction as shown by thearrow WA. Then chuck 405b is also moved in the direction as shown by thearrow WA to make the machined portion of the shaft shaped workpiece 429pass into the workpiece holding portion 405d, to position the chuck 405bnear the chuck 403b, as shown in FIG. 95. The chuck 405b is thenfastened to hold the shaft shaped workpiece 429 with the spindle stock405. At the same time, the chuck 403b is loosened to release the holdingrelation between the spindle stock 403 and the shaft shaped workpiece429. The spindle stock 405 is then moved a predetermined distancetogether with the chuck 405b in the direction as shown by the arrow WBin FIG. 96, that is, in the direction away from the spindle stock 403.The raw portion of the shaft shaped workpiece 429 is thus pulled out apredetermined length from the spindle stock 403 through the chuck 403bin the direction as shown by the arrow WB. After the raw portion of theshaft shaped workpiece 429 is pulled out the predetermined length fromthe spindle stock 403, the workpiece holding portion 403d of the chuck403b is fastened to hold the shaft shaped workpiece 429 with both thespindle stocks 403 and 405. The tool rest 415 is then properly rotatedin the direction as shown by the arrow WI or in the direction as shownby the arrow WJ to position the tool 416 for milling at a positionfacing the shaft shaped workpiece 429, and the tool 416 is rotated. Thetool rest 415 is then fed a predetermined distance together with thetool 416 in the direction as shown by the arrow WH. Furthermore, thespindle stocks 403 and 405 are synchronously moved in the directions asshown by the arrows WA and WB (the Z axis direction). The millingmachining is then performed on the raw portion of the shaft shapedworkpiece 429 which has been pulled out anew. The chucks 403b and 405bare synchronously rotated a predetermined angle in the directions asshown by the arrows WC and WD, with C-axis control performed toward eachspindle (not shown) of the spindle stocks 403 and 405, so that themilling machining can be performed.

When the milling machining is performed, the portion of the shaft shapedworkpiece 429 to have the milling performed thereon is positioned nearthe chuck 403b or the chuck 405b, and is held. In this state, the shaftshaped workpiece 429 is machined by means of the tool rest 415 and tool416 by having the spindle stocks 403 and 405 synchronously moved in thedirections as shown by the arrows WA and WB. The chuck 403b or 405bfills the role of the center rest, since the workpiece 429 is alwaysmachined at a position near the chuck 403b or 405b. Accordingly, thegeneration of chattering can be efficiently prevented on the workpiece429 during the machining, and the machining can be performed withaccuracy.

When the shaft shaped workpiece 429 has been machined along thepredetermined length, the tool rest 415 is retracted from the shaftshaped workpiece 429. A tool 416 for cutting-off, installed on the toolrest 413, is then positioned to face the shaft shaped workpiece 429.Next, the spindle stock 405 is moved in the direction as shown by thearrow WA again, to hold the workpiece 429. Furthermore, the workpieceholding portion 403d of the chuck 403b is loosened to release theholding relation between the spindle stock 403 and the shaft shapedworkpiece 429. In this state the spindle stock 405 is moved apredetermined distance together with the chuck 405b in the direction ashown by the arrow WB. Then the raw portion of the shaft shapedworkpiece 429 is pulled out a predetermined length through the chuck403b of the spindle stock 403 in the direction as shown by the arrow WBby the spindle stock 405. After the raw portion is pulled thepredetermined length from the spindle stock 403, the workpiece holdingportion 403d of the chuck 403b is fastened to hold the shaft shapedworkpiece 429 by the spindle stocks 403 and 405. When the shaft shapedworkpiece 429 is held by the spindle stocks 403 and 405, the spindlestocks 403 and 405 are moved together with the shaft shaped workpiece429 in the directions as shown by the arrows WA and WB (that is, the Zaxis direction). The portion of the shaft shaped workpiece 429 to be cutoff (the boundary position between the machined portion and the rawportion) faces the cutting tool 416 installed in the tool rest 413. Thechucks 403b and 405b, as shown in FIG. 97, are then synchronouslyrotated together with the shaft shaped workpiece 429 in the direction asshown by the arrow WC, and the tool rest 413 is fed a predeterminedquantity, together with the cutting tool 416, in the direction as shownby the arrow WH. Then the shaft shaped workpiece 429 is cut by means ofthe tool 416, and the machined portion (it is called the part 429ahereinafter) is cut off from the remaining raw portion of the shaftshaped workpiece 429.

When the shaft shaped workpiece 429 is cut, the tool rest 413 isretracted from the shaft shaped workpiece 429, and the spindle stock 405is moved a predetermined distance together with the chuck 405b in thedirection as shown by the arrow WB. Then the part 429a is moved thepredetermined distance together with the chuck 405b in the direction asshown by the arrow WB, as shown in FIG. 98. The spindle stock 405 ismoved the predetermined distance in the direction as shown by the arrowWA or in the direction as shown by the arrow WB (the Z axis direction).Moreover, the tool rest 415 is fed a predetermined quantity, togetherwith a tool 416, such as a cutting tool, in the direction as shown bythe arrow WH, to machine the left end surface of the part 429a. Inparallel with this, the spindle stock 403 is moved and driven in thedirections as shown by the arrows WA and WB (the Z axis direction).Moreover, the tool rest 413 is moved and driven together with the tool416 in the directions as shown by the arrows WG and WH (the X axisdirection). Thus the same machining as shown in FIG. 92 is performed onthe raw portion of the shaft shaped workpiece 429 held by the chuck403b. Then when the part 429a is machined in the predetermined shape,the chuck 405b is loosened, and the machined part 429a is detached fromthe chuck 405b to remove the part 429a to to the parts catcher 419, asshown at the lower portion of FIG. 99.

In the above-described embodiment, it was mentioned that the shaftshaped workpiece 429 was pulled out in such a manner that only thespindle stock 105 was moved toward the spindle stock 403, in the Z axisdirection, without moving the spindle stock 403 in the Z axis direction.However, this method of moving the spindle stocks 403 and 405 when thepulling out is performed is not critical. Any method of moving isavailable if the distance between the spindle stocks 403 and 405 can benarrowed and extended properly. For example, the spindle stock 405 canbe stopped, and the spindle stock 403 may be moved toward the spindlestock 405 in the Z axis direction. The shaft workpiece 429 may be pulledout in such that both spindle stocks 403 and 405 are moved in the Z axisdirection.

Another embodiment of the complex machine tool will be described in FIG.100 through FIG. 111.

A complex machine tool 501 has a machine body 502 on which a guidesurface 502a is provided on the upper portion thereof, as shown in FIG.100. Two spindle stocks 503 and 505 face each other, and are movably anddrivably provided, independent of each other, in the right and leftdirections in the figure, that is, in the direction as shown by thearrows WA and WB (the Z axis direction) on the guide surface 502a. Twospindles 503a and 505a are provided, rotatable and drivable in thedirections as shown by the arrows WC and WD, with the spindle stocks 503and 505. Two chucks 503b and 505b are rotatably installed in thespindles 503a and 505a, in the directions as shown by the arrows WC andWD.

Two spindle driving motors 503c and 505c are directly connected with thespindles 503a and 505a. Two transducers 503d and 505d for detecting theamount of angular rotation of the spindle motors 503c and 505c in thedirections as shown by the arrows WC and WD are installed on the spindledriving motors 503c and 505c.

Furthermore, a spindle stock feed driving unit 506 is provided with themachined body 502 as shown in FIG. 100. The spindle stock feed drivingunit 506 has nuts 503e and 505e, feed driving motors 507 and 509,driving screws 510 and 511, and the like. That is, each of the nuts 503eand 505e project, in the machine body 502, through the guide surface502a at the lower portions of the spindle stocks 503 and 505 in FIG.100, and is movably disposed together with the spindle stocks 503 and505 in the directions as shown by the arrows WA and WB (the Z axisdirection) in the machine body 502. Female screws (not shown) aredisposed, penetrating in the Z axis direction, that is, in thedirections as shown by the arrows WA and WB, in the nuts 503e and 505e.Two driving screws 510 and 511, of the same pitch, are rotatably fittedin the nuts 503e and 505e in the directions as shown by the arrows WEand WF. Two feed driving motors 507 and 509 are connected with thedriving screws 510 and 511. Two transducers 507a and 509a for detectingthe amount of angular rotation of each of the feed driving motors 507and 509 in the directions as shown by the arrows WE and WF are installedon the feed driving motors 507 and 509. The spindle stocks 503 and 505are moved and driven by the nuts 503e and 505e in the direction as shownby the arrow WA or in the direction as shown by the arrow WB (the Z axisdirection) such that the feed driving motors 507 and 509 are driven torotate the driving screw 510 and 511 in the direction as shown by thearrow WE or in the direction as shown by the arrow WF.

The complex machining machine tool 501 has a main control portion 512 asshown in FIG. 100. A machining program memory 515, a system programmemory 516, a keyboard 517, tool rest control portions 539 and 540, feeddriving motor control portions 519 and 520, C-axis control portions 521and 522 and rotation number control portions 523 and 525 are connectedwith the main control portion 512 through a bus line 513. The tool restcontrol portion 539 is connected with a tool rest 526 as shown in FIG.101. The tool rest control portion 540 connects with the tool rest 527.The feed driving motor 507, as described before, and the transducer 507aconnect with the feed driving motor control portion 519. The feeddriving motor 509 and the transducer 509a connect with the feed drivingmotor control portion 520.

The spindle driving motor 503c and the transducer 503d connect with theC-axis control portion 521. The spindle driving motor 505c and thetransducer 505d connect with the C-axis control portion 522.Furthermore, the spindle driving motor 503c and the transducer 503dconnect with the rotation number control portion 523. The spindledriving motor 505c and the transducer 505d connect with the rotationnumber control portion 525.

The two turret type tool rests 526 and 527 are provided, movable anddrivable only in the directions as shown by the arrows WG and WH (thatis, the X direction), perpendicular to the directions as shown by thearrows WA and WB (the Z axis direction), with the machine body 502 asshown in FIG. 101. Two turret head 526a and 527a are supported to befree to rotate and drive in the directions as shown by the arrows WI andWJ by the tool rests 526 and 527. Plural tools 529 include a turningtool such as a cutting tool, a rotation tool such as a drill and amilling cutter, installed to be attachable and detachable on the turrethead 526a and 527a.

With the above-described structure of the complex machining machine tool501, when machining a workpiece, at first a workpiece 536 to be machinedis attached to the spindle 503a with the chuck 503b, as shown in FIG.100. Thereafter the operator commands the main control portion 512 tostart the machining of the workpiece 536 through the keyboard 517. Then,the main control portion 512 read out a machining program PROcorresponding to the workpiece 536 to be machined from the machiningprogram memory 515, and, the predetermined machining is performed on theworkpiece 536 on the basis of the machining program PRO.

That is, the main control portion 512 as shown in FIG. 100 commands therotation number control portion 523 that the spindle 503a is to berotated in the direction as shown by the arrow WC at a predeterminedrotation number NA provided by the machining program PRO. The rotationnumber control portion 523, on the basis of the command, makes thespindle driving motor 503c rotate together with the spindle 503a in thedirection as shown by the arrow WC. Then a rotation signal RS1 isoutputted to the rotation number control portion 523 from the transducer503d installed on the spindle driving motor 503c every predeterminedrotation angle of the spindle driving motor 503c (that is, the spindle503a). The rotation number control portion 523 counts the input numberof the rotation signal RS1 per hour to obtain the number of the spindle503a and to control the spindle driving motor 503c so that the rotationnumber of the spindle driving motor 503c is equal to the predeterminedrotation number NA.

The main control portion 512 as shown in FIG. 100 commands the feeddriving motor control portion 519 to move the spindle stock 503 apredetermined quantity in the Z axis direction. The feed driving motorcontrol portion 519, on the basis of the command, outputs a drivingsignal WD2 to the feed driving motor 507. Then the feed driving motor507 makes the driving screw 510 rotate and drive in the direction asshown by the arrow WE and in the direction as shown by the arrow WF, andmakes the spindle stock 503 move, by the nut 503e, in the direction asshown by the arrow WA or in the direction as shown by the arrow wB (theZ axis direction). Then a rotation signal RS2 is outputted to the feeddriving motor control portion 519 from the transducer 507 whenever thefeed driving motor 507 (that is, the driving screw 510) is rotated witha predetermined angle in the direction as shown by the arrow WE or inthe direction as shown by the arrow WF. The feed driving motor controlportion 519 counts the input number of the rotation signal RS2, anddetects the quantity of movement of the spindle stock 503 in the Z axisdirection, being in proportion to the rotation angle quantity of thefeed driving motor 507 in the directions as shown by the arrows WE andWF. Accordingly, the rotation of the feed driving motor 507 iscontrolled so that the movement quantity is equal to the movementquantity provided in the machining program PRO.

Furthermore, the main control portion 512 commands the tool rest controlportion 539 to select a tool 529 to be used for the machining and tocontrol the movement quantity of the tool 529 in the X axis direction.Then the tool rest control portion 539 makes the turret head 526a of thetool rest 526 properly rotate in the direction as shown by the arrow WIor in the direction as shown by the arrow WJ in FIG. 102. Thus the tool529 for turning the outside diameter is positioned to face the workpiece536. Moreover, the tool rest 526 is properly moved and driven togetherwith the tool 529 for turning in the directions as shown by the arrowsWG and WH. Then the machining for turning is performed in apredetermined manner on the outside cylindrical portion of the workpiece536 by means of the tool 529.

When the turning has been performed on the outside cylindrical portionof the workpiece 536 as shown in FIG. 102, the tool rest 526 is properlymoved in the direction as shown by the arrow WG to be retracted from theworkpiece 536. In this state the turret head 526a of the tool rest 526is properly rotated in the direction as shown by the arrow WI or in thedirection as shown by the arrow WJ. Thus the tool 529 for turning theinside diameter of the workpiece, such as a drill or a boring tool, ispositioned to face the workpiece 536 as shown in FIG. 103. Next, thetool rest 526 is fed a predetermined distance, together with the tool529, in the direction as shown by the arrow WH in FIG. 103. Furthermore,the spindle stock 501 is properly moved and driven in the directions asshown by the arrows WA and WB (the Z axis direction), holding theworkpiece 536 with the chuck 503b. In this way the inside diameterportion of the workpiece 536 is machined by means of the tool 529. Afterthis machining, the spindle stock 503 is properly moved in the directionas shown by the arrow WA in FIG. 103 to remove the tool 529 from theinside diameter portion of the workpiece 536. The rotation of the chuck503b in the direction as shown by the arrow WC is then stopped, and thetool rest 536 is moved in the direction as shown by the arrow WG to beretracted from the workpiece 536 in preparation for a milling machiningoperation. The tool 529 for milling, installed in the tool rest 536, ispositioned to face the workpiece 536.

When the inside diameter portion of the workpiece 536 has been machinedas shown in FIG. 103, the milling machining, with C-axis control, isperformed on the workpiece 536. That is, the main control portion 512 asshown in FIG. 100 commands the C-axis control portion 512 to return thespindle 503a to its origin. Then the C-axis control portion 521 makesthe spindle driving motor 503c rotate at a low speed in the direction asshown by the arrow WC or in the direction as shown by the arrow WD.

When the spindle 503a reaches a predetermined position an origindetecting signal OS1 is outputted for the C-axis control portion 521from the transducer 503d. The C-axis control portion 521, on the basisof the signal, immediately stops the rotational driving of the spindledriving motor 503c in the direction as shown by the arrow WC or in thedirection as shown by the arrow WD. Then the spindle 503a stops itsrotation in the direction as shown by the arrow WC or in the directionas shown by the arrow WD, and a predetermined standard position WSP1 ofthe spindle 503a is positioned at the C-axis origin WCZP, as shown inFIG. 110.

Next, the main portion 512 drives the tool rest control portion 539, andthe tool rest 526 as shown in FIG. 104 is moved a predetermined distancein the direction as shown by the arrow WH, with the tool 529 for millingrotating. Furthermore, the spindle stock 503 is properly moved anddriven in the direction as shown by the arrow WB. A channel 536a is thenformed on the outside surrounding portion of the workpiece 536 by meansof the tool 529, spaced a predetermined angle WO1 from the C-axis originWCZP in the direction as shown by the arrow WD as shown in FIG. 110.When the channel 536a has been formed, the tool rest 526 is properlymoved in the direction as shown by the arrow WG to make the tool 529retract from the workpiece 536. Next, the main control portion 512outputs a C-axis control signal CS1 to the C-axis control portion 521,as shown in FIG. 100. Then the C-axis control portion 521 makes thespindle driving motor 503c rotate together with the spindle 503a at alow speed in the direction as shown by the arrow WC. A rotation signalRS3 is outputted to the C-axis control portion 521 from the transducer503d every predetermined rotation angle of the spindle motor 503c. TheC-axis control portion 521 counts the input number of the rotationsignal RS3 to detect the amount of angular rotation of the spindle 503a.The C-axis control portion 521 stops the rotation of the spindle drivingmotor 503c in the direction as shown by the arrow WC when the amount ofangular rotation reaches a predetermined angular rotation quantity W02.Then the spindle 503a stops its rotation in the direction as shown bythe arrow WC, together with the workpiece 536 and the spindle 503a (thatis, the workpiece 536) is positioned at a position rotated thepredetermined angle W82 in the direction as shown by the arrow WC fromthe C-axis origin WCZP.

Thereafter the tool rest 526, being retracted, is moved a predetermineddistance together with the tool 529 for milling toward the workpiece 536in the direction as shown by the arrow WH in FIG. 104. Furthermore, thespindle stock 503 is properly moved and driven in the direction as shownby the arrow WB. Then a channel 536b is formed on the outsidesurrounding portion of the workpiece 536, separated from the channel536a formed before with the predetermined angle WΘ2 in the direction asshown by the arrow WD in FIG. 110.

When the first routine of the machining is finished after the milling ofthe workpiece 536, the main control portion 512 calls a workpiecedelivery program WTP from the system program memory 516 as shown in FIG.100, and the workpiece delivery program WTP is executed. That is, themain control portion 512 commands the C-axis control portion 521 toposition the spindle 503a at a delivery position WCP (see FIG. 110).Then the C-axis control portion 521, on the basis of the command, drivesthe spindle driving motor 503c. The spindle 503a is then slowly rotatedtogether with the workpiece 536 in the direction as shown by the arrowWC or in the direction as shown by the arrow WD. The transducer 503d,being installed on the spindle driving motor 503c, outputs a rotationsignal RS4 to the C-axis control portion 521 every predeterminedrotation angle of the spindle driving motor 503c in the direction asshown as shown by the arrow WC or in the direction as shown by the arrowWD.

Then the C-axis control portion 521 counts the input number of therotation signal RS4, and obtains the position of the spindle drivingmotor 503c relative to the C-axis origin WCZP of the spindle 503a (seeFIG. 110). When the standard position WSP1 of the spindle 503a ispositioned at the delivery position WCP, spaced from the C-axis originWCZP with a predetermined angle Wα in the direction as shown by thearrow WC, a stop signal ST1 is outputted to the spindle driving motor503c, as shown in FIG. 100. Then the spindle driving motor 503c, on thebasis of the signal, stops the rotation in the direction as shown by thearrow WC or in the direction as shown by the arrow WD. As a result, thespindle 503a stops the rotation in the direction as shown by the arrowWC or in the direction as shown by the arrow WD together with theworkpiece 536, and the spindle 503a is positioned at the deliveryposition WCP. Incidentally the C-axis origin (Wα=0) can also be selectedas the delivery position WCP.

The main control 512 as shown in FIG. 100 also commands the C-axiscontrol portion 522 to position the spindle 505a at the deliveryposition WCP (see FIG. 111). Then the C-axis control portion 522 asshown in FIG. 100 makes the spindle driving motor 505c rotate togetherwith spindle 505a at a low speed in the direction as shown by the arrowWC or in the direction as shown in the arrow WD, and detects the amountof angular rotation with the transducer 505d. The position, in thedirections as shown by the arrows WC and WD, relative to the C-axisorigin WCZP cf the spindle 505a as shown in FIG. 111 is obtained on thebasis of the detected rotation angular quantity. When a standardposition WXP2 of the spindle 505a is positioned at the delivery positionWCP, spaced from the C-axis origin WCZP a predetermined angle W2 in thedirection as shown by the arrow WC, the rotation of the spindle drivingmotor 505c is stopped. Then the spindle 505a stops its rotation in thedirection as shown by the arrow WC or in the direction as shown by thearrow WD to be positioned at the delivery position WCP.

When the standard positions WSP1 and WSP2 of the spindles 503a and 505aare positioned at the delivery position WCP, the chuck 505b of thespindle 505a as shown in FIG. 104 is loosened. The spindle stock 505 isthen moved together with the spindle 505a in the direction as shown bythe arrow WA in FIG. 104. There the spindle 505a approaches the spindle503a. The chuck 505b is then fastened to hold the workpiece 536 with thechucks 503b and 505b.

When the workpiece 536 is held by the chucks 503b and 505b, the holdingrelation between the workpiece 536 and the chuck 503b is released. Thespindle stock 505 is then moved a predetermined distance in thedirection as shown by the arrow WB, that is, in the direction going awayfrom the spindle stock 503, with the workpiece 536 held by the chuck505b. Thus the spindle 530a is separated from the spindle 505a, as shownin FIG. 105. The workpiece 536 has then been transferred to the side ofthe spindle 505b. This transfer movement of the workpiece 536 isperformed in such a manner that the spindles 503a and 505a are bothpositioned at the predetermined delivery position WCP, and the workpiece536 is directly held by the chuck 505b of the spindle 505a. Thereforethere is no phase shift of the workpiece 536 toward the C-axis originWCZP from the transfer movement.

When the workpiece 536, after the first routine, has been transferred tothe side of the spindle 505a, a second routine of the machining isperformed on the workpiece 536 on the basis of the machining program PROcorresponding to the workpiece 536. At the same time, a raw workpiece536 is installed on the side of the spindle 503a on the chuck 503b, andthe first routine of the machining as described before is performed on anew a new workpiece 536.

That is, the main control portion 512 as shown in FIG. 100 commands therotation number control portion 525 to rotate the spindle 505a apredetermined rotation number NB in the direction as shown by the arrowWC. Then the rotation control portion 525 makes the spindle drivingmotor 505c rotate together with the spindle 505a in the direction asshown by the arrow WC. The rotation number control portion 525 detectsthe rotation number of the spindle driving motor 505c through thetransducer 505d, and controls the spindle driving motor 505c to have thedetected rotation number equal the predetermined rotation number NB.

The main control portion 512, as shown in FIG. 110, drives the feeddriving motor control portion 520 to make the driving screw 511 rotatein the direction as shown by the arrow WE or in the direction as shownby the arrow WF. The spindle stock 505 is then moved in the direction asshown by the arrow WA or in the direction as shown by the arrow WB (theZ axis direction) with the nut 505e. The feed driving motor controlportion 520 detects the movement quantity of the spindle stock 505 withthe transducer 509a, and controls the driving motor 509 on the basis ofthe detected movement quantity. Moreover, turning is performed on theoutside cylindrical portion of the workpiece 536 in a predeterminedmanner by means of the tool 529 such that the main control portion 512drives the tool rest control portion 540 to make the tool rest 527, asshown in FIG. 106, properly move and drive together with the tool 529for turning in the directions as shown by the arrows WG and WH.

The predetermined machining for turning is performed on the rawworkpiece 536 being held by the chuck 503b as shown in FIG. 106 by thespindle stock 503 being properly moved together with with workpiece 536in the direction as shown by the arrow WA or in the direction as shownby the arrow WB (the Z axis direction). The tool rest 526 is properlymoved and driven together with the tool 529 for turning in thedirections as shown by the arrows WG and WH (the Z axis direction), asdescribed before.

When the turning has been performed on each outside cylindrical portionof the workpieces 536 as shown in FIG. 106, respectively, the tool rests526 and 527 are moved and retracted from the workpieces 536 in thedirection as shown by the arrow WG. The tools 529 installed on the toolrests 526 and 527 for turning the inside diameter are positioned to facetheir respective workpieces 536. Thereafter the tool rests 526 and 527are fed a predetermined distance in the direction as shown by the arrowWH in FIG. 107, and the tools 529 for turning the inside diameter facethe right end surface of the raw workpiece 536 and the left end surfaceof the workpiece 536 after the first routine, respectively. Each insidediameter portion of the raw workpiece 536 and the workpiece 536 afterthe first routine is machined in a predetermined manner, with thespindle stocks 503 and 505 moved in the directions as shown by thearrows WB and in the direction as shown by the arrow WA (the Z axisdirection), respectively. After the machining, the spindle stock 503 isproperly moved in the direction as shown by the arrow WA, and thespindle stock 505 is properly moved in the direction as shown by thearrow WB. Thus each tool 529 is removed from each inside diameterportion. Then the tool rests 526 and 527 are moved in the direction asshown by the arrow WG to be retracted from the workpieces 526.Furthermore, the rotation of the chucks 503b and 505b in the directionas shown by the arrow WC is stopped.

Next, a drill machining with C-axis control is performed, by means ofthe same method as the above-described method of FIG. 104, on theworkpiece 536 held by the chuck 505b, as shown in FIG. 108. That is, themain control portion 512 as shown in FIG. 100 commands the C-axiscontrol portion 522 to rotate the spindle driving motor 505c togetherwith the spindle 505a at a low speed in the direction as shown by thearrow WD. Then the standard position WSP2 of the spindle 505a as shownin FIG. 111 is also rotated in the direction as shown by the arrow WD.When the standard position WSP2 corresponds with the C-axis origin WCZP,an origin detecting signal OS2 is outputted to the C axis controlportion 522 from the transducer 505d, as shown in FIG. 100. While thestandard position WSP2 of the spindle 505a coincides with the C-axisorigin WCZP, as shown in FIG. 111, the channels 536a and 536b, formed onthe workpiece 536 during the first routine of the machining, arepositioned at positions space from the C-axis origin WCZP by angles WΘland (WΘ1+WΘ2), respectively in the direction as shown by the arrow WD.Furthermore, the C-axis control portion 522 stops the spindle drivingmotor 505c when the rotation angular quantity of the spindle 505a in thedirection as shown by the arrow WD, detected through the transducer550d, becomes equal to a predetermined angle WΘ3.

Then the standard position WSP2 of the spindle 505a is positioned at aposition spaced from the C-axis origin WCZP by the predetermined angleWΘ3 in the direction as shown by the arrow WD in FIG. 111.

Thereafter, the tool rest 527, as shown in FIG. 108, is moved apredetermined distance toward the workpiece 536 in the direction asshown by the arrow WH, with the tool 529 for drilling being rotated. Thespindle stock 505 is properly moved and driven in the direction as shownby the arrow WA. The workpiece 536 has been delivered to the side of thespindle 505a without a phase shift after the first routine of themachining on the spindle 503a, as described before. Therefore, the hole536c is formed and penetrated in the workpiece 536 exactly spaced fromthe channels 436a and 536b, formed during the first routine, and asshown by the broken line in FIG. 111, with the predetermined angles WΘ3and (WΘ2+WΘ3) in the direction as shown by the arrow WC respectively.

When the second routine of the machining has been performed on theworkpiece 536, the chuck 505b is loosened and the machined workpiece 536is detached from the chuck 505b. The workpiece 536 is thrown into theworkpiece catcher 537, disposed at the lower portion of FIG. 109. Inparallel with this is performed the milling machining with C-axiscontrol on the workpiece 536 being held by the chuck 503b and as shownin FIG. 108 by means of the method as described before. A tool 529, suchas an end mill, installed on the tool rest 526, is used to form thechannels 536a and 536b, as shown in FIG. 110, on the workpiece 536. Inthis way the first routine is performed in parallel with the secondroutine, so that the successive machining is performed on the workpiece536.

In the above-described embodiment, there was mentioned the method ofdelivery wherein when the workpiece 536 was delivered to the side of thespindle 505a from the side of the spindle 503a, the workpiece 536 wasdelivered in such a manner that the spindle stock 505 was moved,together with the spindle 505a, to the spindle 503a of the spindle stock503 in the direction as shown by the arrow WA. However, this method ofdelivery is not critical. Any method is available if the workpiece 536can be delivered such that he spindle stocks 503 and 505 are relativelymoved in the direction as shown by the arrow WA and in the direction asshown by the arrow WB (the Z axis direction) to become close to eachother. For example, the spindle stock 503 can be moved together with thespindle 503a toward the spindle 505 a in the direction as shown by thearrow WB, so that the workpiece 536 may be delivered to the side of thespindle 505a from the side cf the spindle 503a. The spindles 503a and505a can also approach each other in such a manner that the spindlestock 503 is moved in the direction as shown by the arrow WB and thespindle stock 505 is moved in the direction as shown by the arrow WA todeliver the workpiece 536.

The spindles 503a and 505a of the spindle stocks 503 and 505 are rotatedin the direction as shown by the arrow WC and in the direction as shownby the arrow WD, respectively, to position each of the standardpositions WSP1 and WSP2 of the spindles 503a and 505a at the deliverypositions WCP, as shown in FIG. 110 and FIG. 111. In this state theworkpiece 536 is delivered between the spindle stocks 503 and 505.However, the C-axis coordinate values W2 of the delivery positions WCPare changeable with respect to the C-axis origin WCZP, respectively. So,when each of the standard positions WSP1 and WSP2 of the spindles 503aand 505a is positioned at each delivery position WCP, the C-axiscoordinate values W2 of the delivery positions WCP is preset so that theC-axis coordinate values of the clamps (not shown) of the chucks 503band 505b do not coincide with each other. Accordingly, the delivery canbe smoothly performed without interfering the clamps of the chucks 503band 505b with each other, even if the workpiece 536 delivered betweenthe spindle stocks 503 and 505 is short in the directions as shown bythe arrows WA and WB in FIG. 100.

In the above-described embodiment, the workpiece was delivered betweenthe spindles 503a and 505a on the basis of the workpiece deliveryprogram WTP being stored in the system program memory 516. However, inthe command of the delivery of the workpiece, any method is available ifthe workpiece 536 can be directly delivered between the spindles 503aand 505a. For example, the delivery of the workpiece may be performed onthe basis of the machining program PRO, with the machining program PROincluding the contents of the workpiece delivery program WTP stored inthe machining program memory 515.

Another example of the complex machine tool will be described in FIG.112.

A complex machine tool 701 has spindle stocks 702 and 703 as shown inFIG. 112. The spindle stocks 702 and 703 face each other, and areprovided to be free to move and drive in the directions as shown by thearrows WA and WB (the Z axis direction). Spindles 702a and 703a arerotatably and drivably provided with the spindle stocks 702 and 703 inthe directions as shown by the arrows WC and WD. Chucks 702b and 703bare installed on the spindles 702a and 703a. A workpiece 723 is held bythe chucks 702b and 703b between the spindles 702a and 703a. Spindledriving motors 705 and 706, each of which has the same rating torqueTTs, are directly connected with the spindles 702a and 703a. Twotransducers 707 and 709 are connected with the spindle driving motors705 and 706.

Furthermore, the complex machining machine tool 701 has a main controlportion 710, as shown in FIG. 112. A keyboard 712, a system programmemory 713a, a machining program memory 713b, a tool rest controlportion 715, spindle driving motor control portions 716 and 717, spindlestock feed control portions 719 and 720, etc. are connected with themain control portion 710 through a bus line 711. The tool rest controlportion 715 connects with the tool rest 721 as described hereafter. Thetransducer 707 and 709 connect with the spindle driving motor controlportions 716 and 717. Moreover, the spindle stock feed control portions719 and 720 connect with the spindle stocks 702 and 703.

In the upper portion in FIG. 112 the tool rest 721 of the complexmachining machine tool 701 is movably and drivably provided in thedirections as shown by arrows TE and TF (that is, the X axis direction),perpendicular to the directions as shown by the arrows WA and WB (the Zaxis direction). Plural tools 722 are installed on the tool rest 721.

With the above-described constitution of the complex machining machinetool 701, if a predetermined machining for cutting is performed on theworkpiece 723, the workpiece 723 is held between the spindles 702a and703a with the chucks 702b and 703b. Next, the machining of the workpiece723 is commanded to the main control portion 710 through the keyboard712. Then the main control portion 710, on the basis of the command,reads out a machining program memory 713b, and machines the workpiece723 on the basis of the machining program TPRO.

That is, the main control portion 710 directs the spindle stock feedcontrol portions 719 and 720, on the basis of the machining programTPRO, to make the spindle stocks 702 and 703 synchronously move anddrive in the directions as shown by the arrows WA and WB (the Z axisdirection) to position them at a predetermined machining start position.At the same time, the main control portion 710 directs the tool restcontrol portion 715 to position a tool 722 for turning, such as acutting tool, on tool rest 721 at a position facing the workpiece 723.

Thereafter, the main control portion 710 reads out and executes a startcontrol program TPROS stored in the system program memory 713a, so thatthe workpiece 723 as shown in FIG. 112 is rotated in the direction asshown by the arrow WC by energizing each of the spindle motors 705 and706. That is, the main control portion 710 drives the spindle drivingmotor control portion 717 on the basis of the start control programTPROS to drive the spindle driving motor 706 with a torque TT1 that isless than the rating torque TTs of the motor. At the same time, the maincontrol portion 710 commands the spindle driving motor control portion716 to maintain the current position of the spindle driving motor 705 inthe directions as shown by the arrows WC and WD, executing a self-holdfunction of the spindle driving motor 705. The torque TT1 is thenapplied to the workpiece 723 held between the spindles 702a and 703through the spindle 703a and the chuck 703b connected with the spindledriving motor 706.

Thereafter, the main control portion 710, as shown in FIG. 112, directsthe spindle driving motor control portion 716 on the basis of the startcontrol program TPROS to release the self-hold of the spindle drivingmotor 705 and generate a start torque TTO to the motor 705. Then thespindle driving motor 705 starts to rotate together with the spindle702a in the direction as shown by the arrow WC. The workpiece 723 beingheld between the spindles 702a and 703a also starts to rotate togetherwith the spindles 702a and 703a in the direction a shown by the arrowWC, synchronously. The torque TT1 is already acting on the spindle 703aand the chuck 703b by means of the spindle driving motor 706. Therefore,the spindle 703a and the chuck 703b start to rotate in the direction asshown by the arrow WC by the torque TT1 when the self-hold of thespindle driving motor 705 is released. Accordingly, it is enough thatthe spindle driving motor 705 drives the rotating portion on the side ofthe spindle stock 702, such as the spindle 702a and the chuck 702b. Itis not necessary to start the rotating portion on the side of thespindle stock 703, such as the spindle 703a. As a result it is notnecessary that the workpiece 723 transmit the start torque of the motor705 to the side of the spindle stock 703 from the side of the spindlestock 702, and the inertia of the rotating portion of the side of thespindle stock 703, such as the spindle 703a, the chuck 703b etc., doesnot operate on the workpiece 723, so that the torsional torque acting onthe workpiece 723 is restrained and kept to a minimum.

In this way, when each of the spindle driving motors 705 and 706, asshown in FIG. 112, is energized, and the spindles 702a and 703a arerotated together with the workpiece 723 in the direction as shown by thearrow WC, the main control portion 710 directs the spindle driving motorcontrol portion 716, on the basis of the machining program TPRO, torotate the spindle driving motor 705 together with the spindle 702a withthe rating torque TTs of the motor 705 and with a predetermined rotationnumber TN1 in the direction as shown by the arrow WC. An angularrotation velocity quantity TAV1 of the spindle driving motor 705 in thedirection as shown by the arrow WC is detected through the transducer707, as shown in FIG. 112. The spindle driving motor control portion 716controls the driving motor 705 on the basis of the detected angularrotation velocity quantity TAV1 so that the spindle driving motor 705 isrotated in the direction as shown by the arrow WC with the predeterminedrotation number TN1.

At the same time, the main control portion 710 directs the spindledriving motor control portion 717 to rotate the spindle driving motor706 together with the spindle 703a with a driving torque TT2 (forexample, a torque corresponding to 50% of the rating torque TTs), whichis smaller than the rating torque TTs of the spindle motor 705, in thedirection as shown by the arrow WC.

The torque acting on the spindle 703a through the spindle driving motor706 is smaller than the torque acting on the spindle 702a due to thespindle driving motor 705. Therefore the spindle 703a is rotated withthe same rotation number TN1 as the spindle 702a in the direction asshown by the arrow WC, by the chucks 702b and 703b and the workpiece723.

That is, the rotation of the spindle 702a in the direction as shown bythe arrow WC is the main rotation. The spindle 703a is rotated in thedirection as shown by the arrow WC so as to follow the spindle 702a.Therefore, even if the rotation angular velocity quantity of the spindle702a in the direction as shown by the arrow WC changes according to thecommand of the spindle driving motor control portion 716, through thespindle driving motor 705, so as to keep the predetermined rotationnumber TN1, the driving motor 706 can not oppose the rating torque TTsof the spindle 702a, because motor 706 is driven with the driving torqueTT2, smaller than the rating torque TTs. Accordingly, the angularrotation velocity of the spindle 703a is made to coincide with theangular rotation velocity of the side of the spindle 702a. As a result,the angular rotation velocity of the spindle 703a is controlled by thespindle 702a, that is, the spindle driving motor 705, so that thespindle driving motor 706 cannot positively change the angular velocityof the spindle 703a.

Therefore, the spindles 702a and 703a are always synchronously rotatedin the directions as shown by the arrow WC, with the rotation of thespindle 702a being the main rotation, and the rotation of the spindle703a is being secondary, so that the torsional torque acting on theworkpiece 723 is kept restrained to a minimum.

In this way, when the workpiece 723 held between the spindles 702a and703a is rotated in the direction as shown by the arrow WC in FIG. 112with the predetermined rotation number TN1, the main control portion710, on the basis of the machining program TPRO, directs the spindlestock feed control portions 719 and 720 to synchronously drive and movethe spindle stocks 702 and 703 in the directions as shown by the arrowsWA and WB (the Z axis direction), and directs the tool rest controlportion 715 to drive and move the tool rest 721, together with a tool722 for turning, in the directions as shown by the arrows TE and TF. Inthis way, a predetermined machining for turning is performed on theoutside cylindrical portion of the workpiece 723 by means of the tool722.

An example of a control for a spindle being provided with each spindlestock in a complex machine tool will be described in FIGS. 113 and 114.

A complex machine tool 801 has a spindle stock 809 as shown in FIG. 114.A spindle 802 is rotatably supported on the spindle stock 809 by abearing 810. A rotor 811a of a spindle driving motor 811 is disposed atthe spindle 802. The spindle 802 is a so-called built-in type spindle. Astator 811b is disposed to surround and cover the rotor 811a. Moreover,a pulse generator 812 is disposed at the left side of the spindle 802 asseen in the figure. A gear wheel 802 is fixed to the left of the pulsegenerator 812. An encoder 813 is meshed with the gear wheel 802a.

An amplifier 815 connects with the spindle driving motor 811 and thepulse generator 812, as shown in FIG. 113. A transfer switch 816 isconnected with the amplifier 815. A spindle control portion 817, whichcontrols the spindle driving motor 811 at the time of turning, and aC-axis control portion 819, which controls the spindle driving motor 811at the time of C-axis control, are connected with the transfer switch816. The encoder 813 connects with the C-axis control portion 819.

With the above-described constitution of the complex machine tool 801,when turning, the transfer switch 816 is pushed up at the side of thespindle control portion 817, and the spindle control portion 817connects with the amplifier 815, as shown in FIG. 113. Then a controlsignal SS1 is inputted to the amplifier 815 through the transfer switch816 from the side of the spindle control portion 817. Moreover, thesignal SS2, amplified by means of the amplifier 815, is inputted to thespindle driving motor 811, and the spindle driving motor 811 is rotatedwith a predetermined rotation number. Thus the machining for turning isperformed. The rotation number of the spindle 802 is detected from thepulse generator 812, and the rotation number is fed back to theamplifier 815. Moreover, the amplifier 815 controls the spindle drivingmotor 811 on the basis of the output of the pulse generator 812, so thatthe spindle driving motor 811 is exactly rotated with the rotationnumber corresponding to the signal SS1.

Next, in the case of the machining with C-axis control, the transferswitch 816 is transferred to the side of the C-axis control portion 819from the side of the spindle control portion 817, at which point thetransfer switch was until now, and the C-axis control portion 819 isconnected with the amplifier 815 through the transfer switch 816. Inthis state, a control signal SS2 for C-axis control is outputted to theamplifier 815 from the C-axis control portion 819 through the transferswitch 816, and the amplifier 815 makes the spindle driving motor 811rotate at the predetermined speed. In this way, the machining, such as apredetermined milling machining, is performed.

In the above-described embodiment, it was mentioned that the presentinvention was applied to a so-called built-in type machine tool, ofwhich the spindle driving motor 811 is built into the spindle 802. Butthe machine tool is not restricted to the built-in type. The presentinvention can naturally apply to a machine tool arranged so that thespindle driving motor 811 and the spindle 802 are provided separately,and the torque is transmitted to the spindle 802 by means of a gear, abelt or the like.

An example of a coordinate system control method in a complex machinetool will be described in FIG. 115 and FIG. 116.

A machine tool 301 has a main control portion 302 as shown in FIG. 115.A display portion 305 such as a display, an input portion 306 such as akeyboard, a tool rest form memory 333, a machining program memory 307, achuck form memory 309, a machining standard position coordinates memory310, a tool form memory 311, a raw material form memory 336, a robotcontrol program memory 312, a coordinates relation memory 313, acoordinates operating portion 315, and the like are connected with themain control portion 302 through a bus line 303. A first tool restdriving control portion 316, a second tool rest driving control portion317, a first spindle driving control portion 319, a second spindledriving control portion 320, a robot driving control portion 321, abarfeeder driving control portion 322, and the like are connected withthe coordinates operating portion 315. The machine tool 301 has a firstspindle 323. The first spindle 323 is rotatably and drivably supportedwith a Z₁ axis as its center. A workpiece 325 is held by the firstspindle 323 through a chuck 323a. A second spindle 326 is provided at aposition facing the first spindle 323, and is supported to be free torotate and drive on a Z₂ axis as its center, which coincides with the Z₁axis. The positive and negative directions of the Z₂ axis are providedconversely. A workpiece 327 is held by the second spindle 326 with achuck 326a. The workpiece 327 is a bar shaped workpiece. A barfeeder 329is disposed on the right side of the workpiece 327 in FIG. 115. A firsttool rest 330 and a second tool rest 331 are provided between the firstspindle 323 and the second spindle 326. The first tool rest 330 and thesecond tool rest 331 are movably and drivably provided in the directionas shown by the arrow ZA and in the direction as shown by the arrow ZB,along the X.sub. 1 and X₂ axis, perpendicular to the Z₁ and Z₂ axis. Ahandling robot 332 is movably disposed in the direction of a W₁ and W₂axis, parallel to the Z axis direction, at the lower side of the toolrests 330 and 331 in FIG. 115.

The first spindle 323 is connected with the first spindle drivingcontrol portion 319. The second spindle 326 is connected with thespindle driving control portion 320. The first tool rest 330 isconnected with the first tool rest driving control portion 316. Thesecond tool rest 331 is connected with the second tool rest drivingcontrol portion 317. Moreover, the handling robot 332 is connected withthe robot driving control portion 321. The barfeeder 329 is connectedwith the barfeeder driving control portion 322.

With the above-described constitution of the machine tool 301, whenmachining the workpieces 325 and 327, the main control portion 302 readsout a machining program ZPRO of the workpieces 324 and 327 from themachining program memory 307, and the barfeeder driving control portion322 is driven on the basis of the machining program ZPRO to push out theworkpiece 327 in the direction as shown by an arrow ZC. Thereafter, thesecond spindle 326 is rotated by the second spindle driving controlportion 320 at a predetermined speed indicated by the machining programZPRO, and is moved in the directions as shown by the arrows ZC and ZDalong the Z₂ axis. Then the second tool rest 331 is moved by the secondtool rest driving control portion 317 in the directions as shown by thearrows ZA and ZB along the axis to perform the predetermined machiningon the workpiece 327.

When the predetermined machining is performed on the workpiece 327, thesecond spindle 326 is moved in the direction as shown by the arrow ZC tomake the first spindle 323 hold the end portion of the workpiece 327.The workpiece 327 is then cut off. The cut-off workpiece 325 is held bythe chuck 323a of the first spindle 323. Then the predeterminedmachining on the basis of the machining program ZPRO is performed on theworkpiece 325 held by the first spindle 323. While the machining of theworkpiece 325 is performed by means of the first spindle 323, thebarfeeder 329 is driven, a new workpiece 327 is supplied to the chuck326a, and the predetermined machining on the basis of the machiningprogram ZPRO is performed on the supplied workpiece 327. The workpiece325 on which the machining is finished at the first spindle 323 isdetached from the chuck 323a by means of the handling robot 332,controlled on the basis of a robot control program ZRCP which is readout from the robot control program memory 312, to be thrown into a partscatcher.

At the time of machining, various kinds of coordinate systems to becontrolled, and coordinate system data relating to the coordinatesystems, such as the machining program and parameters, are set in themachine tool 301 as shown in FIG. 116. That is, the coordinate systemsare set as follows:

(a) X₁ -Z₁ axis coordinate system standardizing the mechanical originsZMZP3 and ZMZP5 used when the first spindle 323 is driven and controlledin the directions as shown by the arrows ZC and ZD and the first toolrest 330 is driven and controlled in the directions as shown by thearrows ZA and ZB. (The right and upper sides in FIG. 116 are positive.)

(b) X₂ -Z₂ axis coordinate system standardizing the mechanical originsZMZP2 and ZMZP4 used when the second spindle 326 is driven andcontrolled in the directions as shown by the arrows ZC and ZD and thesecond tool rest 331 is driven and controlled in the directions as shownby the arrows ZA and ZB. (The left hand and upper hand in FIG. 116 arepositive.)

(c) W₁ -W₂ axis coordinate system, used when the hand 332a of thehandling robot 332 is driven and controlled in the directions as shownby the arrows ZC and ZD. (The right and left directions from themechanical origin ZMZP1 are positive.)

Furthermore, the coordinate system data set at each coordinate systemis, for example in the coordinate system of the X₁ -Z₁ axes, dimensiondata P3-P9 showing the dimension form of the chuck 323a, and is amachining program ZPRO₁ for machining the workpiece 325. In thecoordinate system of the X₂ -X₂ axes, the coordinate system data isdimension data P11-P18 showing the dimension form of the chuck 326a, andis a machining program ZPRO₂ for machining the workpiece 327. Thesecoordinate system data, labelled ZCDA, are stored in the chuck formmemory 309 and and the machining program memory 307. In the coordinatesystem of the X₁ -Z₁ axes dimension data P19 and P20 show the dimensionform of the first tool rest 330. In the coordinate system of the X₂ -Z₂axes dimension data P21 and P22 show the dimension form of the secondtool rest 331. Those coordinate system data ZCDA are stored in the toolrest form memory 333. Cutting edge data relating to each tool 335installed on the first tool rest 330, that is, position data P23 and P24at X₁ -Z₁ coordinate between a cutting edge 335a and a machining programorigin ZPZP2, and cutting edge data relating to each tool 335 beinginstalled on the second tool rest 331, that is, position data P25 andP28, at the X₂ -Z₂ coordinate system between a cutting edge 335a and amachining program origin ZPZP1, are stored in the tool form memory 311as coordinate system data ZCDA. Moreover, offset values P26 and P27between workpiece origins ZWZP1 and ZWZP2 of the workpieces 324 and 327and each machining program origin ZPZP1 and ZPZP2, and position data P31and P32 indicating the distance in the direction of the Z axis betweenthe machining program origins ZPZP2 and ZPZP1 and the origins ZMZP5 andZMZP4 of each of the tool rests 330 and 331 are stored in the machiningstandard position coordinates memory 310 as coordinate system data ZCDA.

Accordingly, each control object belonging to each coordinate system isusually controlled by means of the coordinate system data ZCDAcorresponding to that coordinate system. However, due to the content ofthe machining program, there may be a case where the control must beperformed by means of the coordinate system data ZCDA set on anothercoordinate system. For example, if the handling robot 332 is driven inthe directions as shown by the arrows ZC and ZD on the basis of thecoordinate system W₁ -W₂, it is necessary that the form of the chucks323a and 326a is acknowledged so as to prevent interference between thehandling robot 332 and the chucks 323a and 326a. The robot drivingcontrol portion 321 controls its movement conditions so that thehandling robot 332 is not excessively driven in the directions as shownby the arrows ZC and ZD. the coordinate system data ZCDA relating to thedimension of the chucks 323a and 326a is stored in the chuck form memory309. However, all the data ZCDA depend on the coordinate systems X₁ -XZ₁and X₂ -Z₂ to which the chucks 323a and 326a belong, and do not dependon the coordinate system W₁ -W₂ for controlling the handling robot 323.Accordingly, since the handling robot 332 cannot be controlled on thebasis of the coordinate system data ZCDA as it is, the robot drivingcontrol portion 321 requires the coordinates operating portion 315 toconvert the coordinate system data ZCDA relating to the dimension of thechucks 323a and 326a, stored in the chuck form memory 309, into thecoordinate system W₁ -W₂.

The coordinates operating portion 315 then reads out the coordinatesystem data ZCDA relating to the dimension of the chucks 323a and 326afrom the chuck form memory 309 immediately, and reads out coordinateposition relating information ZCLI showing the correlation between thecoordinate system W₁ -W₂ and the coordinate systems X₁ -Z₁ and X₂ -Z₂from the coordinates relation memory 313. Thus the conversion process isperformed so that the coordinate system data ZCDA relating to thedimension of the chucks 323a and 326a, created on the basis of thecoordinate systems X₁ -Z₁ and X₂ -Z₂ is converted to the coordinatesystem W₁ -W₂ on the basis of the coordinate position relatinginformation ZCLI read out. Since the coordinate position relatinginformation ZCLI, for example the distances ZR1-ZR8 in the directions asshown by the arrows ZC and ZD and in the directions as shown by thearrows ZA and AB (corresponding to the X axis direction and the Z axisdirection) from the total standard point ZRZP, which is standard for allthe coordinate systems on the machine tool 301, to the standard point ofeach coordinate system, that is, to each origin ZMZP1-ZMZP5, aredisplayed, the coordinates operating portion 315 can immediatelyacknowledge the position relation between the mutual coordinate systemsfrom the coordinate position relating information ZCLI. Thus the form ofthe chucks 323a and 326a is converted on the coordinate system W₁ -W₂ onthe basis of the position relation. Since the coordinate system W₁ -W₂is set only in the directions as shown by the arrows ZC and ZD, thecoordinate system data ZCDA relating to the coordinate systems X₁ -Z₁and X₂ -Z₂ is converted only for the portion relating to the Z axis, andis outputted to the robot driving control portion 321. However, if thecoordinate system data ZCDA of the coordinate system X₁ -Z₁ is convertedto the X₂ -Z₂, the conversion process is performed for both the X axisand the Z axis. Therefore the robot driving control portion 321, forexample, can receive the dimension of the chuck 323a of the firstspindle 323 in the directions as shown by the arrows ZC and ZD such thatthe data P5, on the basis of the Z₁ axis, is converted into thedimension data WP5 on the basis of the W₁ axis on which the mechanicalorigin ZMZP1 has its origin. Thus the robot driving control portion 321can control the handling robot 333 so that it does not interfere withthe chuck 323a.

The coordinate system data ZCDA relating to the coordinate systems X₁-Z₁ and X₂ -Z₂ can also be applicable in the same way. If the firstspindle 232 is moved along the Z₁ axis directions as shown by the arrowsZC and ZD, in order that the tool 335 of the second tool rest 331 doesnot interfere with the workpiece 325, the coordinate operating portion315 always computes the position of the cutting edge of the tool 335 onthe basis of the coordinate system X₁ -Z₁, making use of the coordinateposition relating information ZCLI. Thus the position of the cuttingedge can be monitored. Therefore interference between the workpiece 325and the tool 335 of the second tool rest 331 can be easily prevented.The form of the workpiece 325 can be easily determined from the rawmaterial dimension data inputted to the raw material form memory 326through the input portion 306 on the coordinate system X₁ -Z₁, if theworkpiece 325 is a raw material. During the machining, the machiningprogram ZPRO₁ is analyzed to obtain tool pass data being executed at thetime. Thus the form of the workpiece 325 is easily obtained.

The above-described embodiment explained that the distance ZR1-ZR8 fromthe total standard point ZRZP, being standardized toward all thecoordinate systems on the machine tool 301 to the standard point of eachcoordinate system, were displayed as the position relating informationZCLI, as shown in FIG. 116. However, the distances between the standardpoints of the coordinate systems are displayed as the coordinateposition relating information ZCLI without providing the total standardpoint ZRZP. Thereafter, the coordinate operating portion 315 cannaturally compute on the basis of the distances.

The method of measuring the position relation between the mechanicalorigin ZMZP1 of the handling robot 333 and the other coordinate systemsas the coordinate position relating information ZCLI is as follows: thestandard surface of the robot hand 332a comes into contact with thecutting edge of the tool 335a and a tool length measuring means, ofwhich the position data is known on the X₁ -Z₁ coordinate system. Theposition relation can then be gotten from the position of the cuttingedge 335a on the X₁ -Z₁ coordinate system and the position of the hand332a and the W₁ -W₂ coordinate system at that time. The other positionrelation data is also obtained by this method. For example, the toolrest 330 is moved in the X₁ direction and the hand 332a is moved in theW₁ direction to bring the cutting edge 335a of the tool into contactwith the hand standard surface. Then the distance ZR1 between the originZMZP1 of the robot 332 and the total standard point ZRZP becomesimmediately clear from the equation P30+ZR1=ZR4+P31 -P23. That is, thedistance ZR1 is found making use of the distance ZR4 between the originZMZP5 of the tool rest 330 and the total standard position ZRZP at thetime, the position data P23 between the cutting edge 335a and theprogram origin ZPZP2, the position data P31 between the program originZPZP2 and the mechanical origin ZMZP5, and the coordinate position P30of the hand 332a on the W₁ -W₂ coordinate system.

The coordinate system control method according to the present inventioncan be, of course, used for any purpose, as long as the coordinatesystem data ZCDA belonging to the different coordinate systems (All ofthe dimension information belonging to one coordinate system can be thecoordinate system data ZCDA. Accordingly, the machining program ZPRO andthe robot control program ZRCP are also regarded as the coordinatesystem data ZCDA if created on the basis of a specific coordinatesystem.) is converted into the coordinate system of one object to becontrolled on the coordinate system, on the basis of the coordinateposition relating information ZCLI in the machine tool. The coordinatesystem control method can be also applied for various kinds of barriersand the prevention of interference, the teaching of the handling robot,and when machining the workpiece 327 installed in the second spindle 326by means of a tool 335 installed on the first tool rest 330 (In thiscase, the command of the tool path relating to the machining of theworkpiece 327 is converted into the coordinate system X₁ -Z₁ from thecoordinate system X₂ -Z₂ to make the first tool rest 330 machine.), andthe like.

We claim:
 1. A lathe, comprising:a frame; first and second spindlestocks having first and second workpiece spindles rotatably supportedthereby, respectively, said first and second spindle stocks beingdisposed on said frame so as to face each other and so as to be free tomove only in a direction along axis centers of said first and secondworkpiece spindles, said axis centers of said first and second workpiecespindles being colinear; first and second workpiece holding meansprovided with said first and second workpiece spindles, respectively,for holding a single workpiece between said first and second spindlestocks; at least one tool rest capable of selectively positioning toolsfor said first and second workpiece holding means; first and second feedscrews rotatably disposed on said frame, said first and second spindlestocks being engaged with said first and second feed screws,respectively, for independently moving said first and second spindlestocks in said direction of said axis centers of said workpiece spindleby rotation of said feed screws; first and second means for rotatablydriving said first and second feed screws, respectively, connected withsaid first and second feed screws; a rotation angular quantity detectingmeans for electrically detecting the angular rotation of both said firstand said second feed screws, and for outputting a signal correspondingto the angular rotation of said first and said second feed screws; asynchronous movement control means for controlling at least one of saidfirst and said second means for rotatably driving said first and saidsecond feed screws so that said first and second spindle stockssynchronously move at the same speed in the same direction upon rotationof said first and second feed screws by said first and second means forrotatably driving while a single workpiece is held between said firstand second spindle stocks on the basis of said signal outputted fromsaid rotation angular quantity detecting means; and synchronous movementcommand means for commanding said synchronous movement control means tosynchronously move said first and second spindle stocks.
 2. The lathe ofclaim 1, and further comprising rotational angle control means forcontrolling the amount of angular rotation of said first and secondworkpiece spindles.
 3. The lathe of claim 1, wherein said rotationangular quantity detecting means comprises a rotary encoder on each saidfeed screw detecting the quantity of angular rotation of said feedscrews.
 4. The lathe of claim 3, wherein each said rotary encodercomprises a rotating disc connecting to its respective said feed screwand a sensor sensing the rotation of said rotating disc.
 5. The lathe ofclaim 1, wherein said first and said second means for rotatably drivingsaid first and said second feed screws comprise respective motors, andsaid synchronous movement control means controls one said motor on thebasis of the speed of said feed screw of the other said motor.
 6. Thelathe of claim 5, wherein said synchronous movement control means checksand maintains the synchronous rotation of said feed screws by minimizingthe difference between the detected quantity of angular rotation of saidfeed screws.
 7. A lathe, comprising:a frame; first and second spindlestocks having first and second workpiece spindles rotatably supportedthereby, respectively, said first and second spindle stocks beingdisposed on said frame so as to face each other and so as to be free tomove only in a direction along axis centers of said first and secondworkpiece spindles, said axis centers of said first and second workpiecespindles being colinear; first and second workpiece holding meansprovided with said first and second workpiece spindles, respectively,for holding a single workpiece between said first and second spindlestocks; at least one tool rest capable of selectively positioning toolsfor said first and second workpiece holding means; first and second feedscrews rotatably disposed on said frame, said first and second spindlestocks being engaged with said first and second feed screws,respectively, for independently moving said first and second spindlestocks in said direction of said axis centers of said workpiece spindleby rotation of said feed screws; first and second means for rotatablydriving said first and second feed screws, respectively, connected withsaid first and second feed screws; and a clutch means for operablyconnecting said first and second feed screws together so that said firstand second spindle stocks move at the same speed in the same directionupon rotation of one of said first and second feed screws by one of saidfirst and second means for rotatably driving while a single workpiece isheld between said spindle stocks and for disconnecting said first andsecond feed screws.
 8. The lathe of claim 7, and further comprisingrotational angle control means for controlling the amount of angularrotation of said first and second workpiece spindles.
 9. The lathe ofclaim 7, wherein each of said feed screw has a gear at an end thereofand said clutch means comprises a rotatable shaft with clutch gearsfixed thereto for engagement with respective said gears of said feedscrews.
 10. The lathe of claim 9, wherein said first and second meansfor rotatably driving said first and second feed screws compriserespective drive motors.
 11. The lathe of claim 10, wherein said firstand second feed screws are connected to said first and second spindlestocks with respective nuts.